diff --git a/include/picrin/irep.h b/include/picrin/irep.h
index 14378424..f870d54f 100644
--- a/include/picrin/irep.h
+++ b/include/picrin/irep.h
@@ -3,7 +3,7 @@
 
 enum pic_instruction {
   OP_PUSHNIL,
-  OP_PUSHI,
+  OP_PUSHNUM,
   OP_PUSHUNDEF,
   OP_GREF,
   OP_GSET,
@@ -16,6 +16,7 @@ enum pic_instruction {
 struct pic_code {
   enum pic_instruction insn;
   union {
+    double f;
     int i;
     struct pic_pair *gvar;
   } u;
diff --git a/include/picrin/value.h b/include/picrin/value.h
index a85d6660..2bca6f0a 100644
--- a/include/picrin/value.h
+++ b/include/picrin/value.h
@@ -3,7 +3,7 @@
 
 enum pic_vtype {
   PIC_VTYPE_NIL,
-  PIC_VTYPE_INT,
+  PIC_VTYPE_FLOAT,
   PIC_VTYPE_UNDEF,
   PIC_VTYPE_HEAP
 };
@@ -12,14 +12,14 @@ typedef struct {
   enum pic_vtype type;
   union {
     void *data;
-    int i;
+    double f;
   } u;
 } pic_value;
 
 enum pic_tt {
   /* immediate */
   PIC_TT_NIL,
-  PIC_TT_INT,
+  PIC_TT_FLOAT,
   PIC_TT_UNDEF,
   /* heap */
   PIC_TT_PAIR,
@@ -56,9 +56,9 @@ enum pic_tt pic_type(pic_value);
 pic_value pic_nil_value();
 pic_value pic_undef_value();
 pic_value pic_obj_value(void *);
-pic_value pic_int_value(int);
+pic_value pic_float_value(double);
 
-#define pic_int(v) ((v).u.i)
+#define pic_float(v) ((v).u.f)
 
 #define pic_nil_p(v) (pic_type(v) == PIC_TT_NIL)
 
diff --git a/src/eval.c b/src/eval.c
index 637f1c8b..2d1926ab 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -74,7 +74,7 @@ pic_eval(pic_state *pic, pic_value obj, struct pic_env *env)
 	/* not implemented */
       }
     }
-    case PIC_TT_INT:
+    case PIC_TT_FLOAT:
     case PIC_TT_NIL: {
       return obj;
     }
diff --git a/src/parse.y b/src/parse.y
index e30b3e3c..bff7e832 100644
--- a/src/parse.y
+++ b/src/parse.y
@@ -19,10 +19,10 @@ struct parser_control {
 }
 
 %token tLPAREN tRPAREN tDOT
-%token <datum> tSYMBOL tINT
+%token <datum> tSYMBOL tNUMBER
 
 %type <datum> datum simple_datum symbol compound_datum
-%type <datum> number integer list list_tail
+%type <datum> number list list_tail
 
 %%
 
@@ -55,14 +55,7 @@ symbol
 ;
 
 number
-	: integer
-;
-
-integer
-	: tINT
-	{
-	  $$ = $1;
-	}
+	: tNUMBER
 ;
 
 compound_datum
@@ -106,7 +99,6 @@ pic_parse(pic_state *pic, const char *str)
   struct parser_control p;
 
   p.pic = pic;
-  p.value = pic_int_value(42);
 
   yy_scan_string(str);
   yyparse(&p);
diff --git a/src/scan.l b/src/scan.l
index a3300a0e..8b4aba98 100644
--- a/src/scan.l
+++ b/src/scan.l
@@ -19,7 +19,7 @@ struct parser_control {
 [ \t\n\r]	/* skip whitespace */
 "("	return tLPAREN;
 ")"	return tRPAREN;
-[1-9][0-9]*	{ yylval.datum = pic_int_value(atoi(yytext)); return tINT; }
+[1-9][0-9]*	{ yylval.datum = pic_float_value(atoi(yytext)); return tNUMBER; }
 [a-z0-9A-Z]+	{ yylval.datum = pic_intern_cstr(p->pic, yytext); return tSYMBOL; }
 
 %%
diff --git a/src/value.c b/src/value.c
index fe8c996e..9b8becfd 100644
--- a/src/value.c
+++ b/src/value.c
@@ -8,8 +8,8 @@ pic_type(pic_value v)
   switch (v.type) {
   case PIC_VTYPE_NIL:
     return PIC_TT_NIL;
-  case PIC_VTYPE_INT:
-    return PIC_TT_INT;
+  case PIC_VTYPE_FLOAT:
+    return PIC_TT_FLOAT;
   case PIC_VTYPE_UNDEF:
     return PIC_TT_UNDEF;
   case PIC_VTYPE_HEAP:
@@ -38,12 +38,12 @@ pic_obj_value(void *ptr)
 }
 
 pic_value
-pic_int_value(int i)
+pic_float_value(double f)
 {
   pic_value v;
 
-  v.type = PIC_VTYPE_INT;
-  v.u.i = i;
+  v.type = PIC_VTYPE_FLOAT;
+  v.u.f = f;
   return v;
 }
 
diff --git a/src/vm.c b/src/vm.c
index 2c47063b..5a1c29d3 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -100,8 +100,8 @@ print_irep(pic_state *pic, struct pic_irep *irep)
     case OP_PUSHNIL:
       puts("OP_PUSHNIL");
       break;
-    case OP_PUSHI:
-      printf("OP_PUSHI\t%d\n", irep->code[i].u.i);
+    case OP_PUSHNUM:
+      printf("OP_PUSHNUM\t%f\n", irep->code[i].u.f);
       break;
     case OP_PUSHUNDEF:
       puts("OP_PUSHUNDEF");
@@ -190,9 +190,9 @@ pic_gen(pic_state *pic, struct pic_irep *irep, pic_value obj, struct pic_env *en
       break;
     }
   }
-  case PIC_TT_INT: {
-    irep->code[irep->clen].insn = OP_PUSHI;
-    irep->code[irep->clen].u.i = pic_int(obj);
+  case PIC_TT_FLOAT: {
+    irep->code[irep->clen].insn = OP_PUSHNUM;
+    irep->code[irep->clen].u.f = pic_float(obj);
     irep->clen++;
     break;
   }
@@ -283,8 +283,8 @@ pic_run(pic_state *pic, struct pic_proc *proc, pic_value args)
       PUSH(pic_nil_value());
       NEXT;
     }
-    CASE(OP_PUSHI) {
-      PUSH(pic_int_value(pc->u.i));
+    CASE(OP_PUSHNUM) {
+      PUSH(pic_float_value(pc->u.f));
       NEXT;
     }
     CASE(OP_PUSHUNDEF) {
@@ -322,7 +322,7 @@ pic_run(pic_state *pic, struct pic_proc *proc, pic_value args)
       pic_value a, b;
       a = POP();
       b = POP();
-      PUSH(pic_int_value(pic_int(a) + pic_int(b)));
+      PUSH(pic_float_value(pic_float(a) + pic_float(b)));
       NEXT;
     }
     CASE(OP_STOP) {
diff --git a/src/write.c b/src/write.c
index a6ca251c..2aaa84b8 100644
--- a/src/write.c
+++ b/src/write.c
@@ -21,8 +21,8 @@ pic_debug(pic_state *pic, pic_value obj)
   case PIC_TT_SYMBOL:
     printf("%s", pic_symbol_ptr(obj)->name);
     break;
-  case PIC_TT_INT:
-    printf("%d", pic_int(obj));
+  case PIC_TT_FLOAT:
+    printf("%f", pic_float(obj));
     break;
   case PIC_TT_UNDEF:
     printf("#<undef>");