diff --git a/include/picrin.h b/include/picrin.h
index 6f8dbb94..5ef6b53b 100644
--- a/include/picrin.h
+++ b/include/picrin.h
@@ -68,18 +68,18 @@ typedef struct {
   struct pic_env *env;
 } pic_callinfo;
 
-struct pic_block {
+typedef struct pic_block {
   struct pic_block *prev;
   int depth;
   struct pic_proc *in, *out;
   unsigned refcnt;
-};
+} pic_block;
 
 typedef struct {
   int argc;
   char **argv, **envp;
 
-  struct pic_block *blk;
+  pic_block *blk;
 
   pic_value *sp;
   pic_value *stbase, *stend;
diff --git a/include/picrin/cont.h b/include/picrin/cont.h
index dd43607b..3e7b0360 100644
--- a/include/picrin/cont.h
+++ b/include/picrin/cont.h
@@ -13,7 +13,7 @@ struct pic_cont {
   PIC_OBJECT_HEADER
   jmp_buf jmp;
 
-  struct pic_block *blk;
+  pic_block *blk;
 
   pic_value *stk_pos, *stk_ptr;
   size_t stk_len;
@@ -40,7 +40,7 @@ struct pic_cont {
   } while (0)
 
 #define PIC_BLK_DECREF(pic,blk) do {			\
-    struct pic_block *_a = (blk), *_b;			\
+    pic_block *_a = (blk), *_b;			\
     while (_a) {					\
       if (! --_a->refcnt) {				\
 	_b = _a->prev;					\
diff --git a/src/cont.c b/src/cont.c
index 88bf3a7b..12b96d56 100644
--- a/src/cont.c
+++ b/src/cont.c
@@ -182,7 +182,7 @@ restore_cont(pic_state *pic, struct pic_cont *cont)
 }
 
 static void
-walk_to_block(pic_state *pic, struct pic_block *here, struct pic_block *there)
+walk_to_block(pic_state *pic, pic_block *here, pic_block *there)
 {
   if (here == there)
     return;
@@ -282,10 +282,10 @@ pic_cont_dynamic_wind(pic_state *pic)
   /* enter */
   pic_apply_argv(pic, in, 0);
   {
-    struct pic_block *here;
+    pic_block *here;
 
     here = pic->blk;
-    pic->blk = (struct pic_block *)pic_alloc(pic, sizeof(struct pic_block));
+    pic->blk = (pic_block *)pic_alloc(pic, sizeof(pic_block));
     pic->blk->prev = here;
     pic->blk->depth = here->depth + 1;
     pic->blk->in = in;
diff --git a/src/gc.c b/src/gc.c
index 1cce8404..ec830474 100644
--- a/src/gc.c
+++ b/src/gc.c
@@ -318,7 +318,7 @@ static void gc_mark(pic_state *, pic_value);
 static void gc_mark_object(pic_state *pic, struct pic_object *obj);
 
 static void
-gc_mark_block(pic_state *pic, struct pic_block *blk)
+gc_mark_block(pic_state *pic, pic_block *blk)
 {
   while (blk) {
     if (blk->in)
diff --git a/src/state.c b/src/state.c
index 7c468306..428b6229 100644
--- a/src/state.c
+++ b/src/state.c
@@ -28,7 +28,7 @@ pic_open(int argc, char *argv[], char **envp)
   pic->envp = envp;
 
   /* root block */
-  pic->blk = (struct pic_block *)malloc(sizeof(struct pic_block));
+  pic->blk = (pic_block *)malloc(sizeof(pic_block));
   pic->blk->prev = NULL;
   pic->blk->depth = 0;
   pic->blk->in = pic->blk->out = NULL;
diff --git a/src/system.c b/src/system.c
index afe4301a..2591fa20 100644
--- a/src/system.c
+++ b/src/system.c
@@ -31,7 +31,7 @@ pic_system_exit(pic_state *pic)
 {
   pic_value v;
   int argc, status = EXIT_SUCCESS;
-  struct pic_block *blk;
+  pic_block *blk;
 
   argc = pic_get_args(pic, "|o", &v);
   if (argc == 1) {