diff --git a/lib/nghttp2_pq.c b/lib/nghttp2_pq.c
index a738084b..54c3eca4 100644
--- a/lib/nghttp2_pq.c
+++ b/lib/nghttp2_pq.c
@@ -180,8 +180,3 @@ int nghttp2_pq_each(nghttp2_pq *pq, nghttp2_pq_item_cb fun, void *arg) {
   }
   return 0;
 }
-
-void nghttp2_pq_increase_key(nghttp2_pq *pq, nghttp2_pq_entry *item) {
-  assert(pq->q[item->index] == item);
-  bubble_down(pq, item->index);
-}
diff --git a/lib/nghttp2_pq.h b/lib/nghttp2_pq.h
index f4cb6db3..6b0ecfb4 100644
--- a/lib/nghttp2_pq.h
+++ b/lib/nghttp2_pq.h
@@ -120,12 +120,6 @@ void nghttp2_pq_update(nghttp2_pq *pq, nghttp2_pq_item_cb fun, void *arg);
  */
 int nghttp2_pq_each(nghttp2_pq *pq, nghttp2_pq_item_cb fun, void *arg);
 
-/*
- * Performs "increase-key" operation against |item|, assuming |item|
- * is in |pq|, and its key is already updated.
- */
-void nghttp2_pq_increase_key(nghttp2_pq *pq, nghttp2_pq_entry *item);
-
 /*
  * Removes |item| from priority queue.
  */
diff --git a/tests/main.c b/tests/main.c
index 9ca387d2..7239f995 100644
--- a/tests/main.c
+++ b/tests/main.c
@@ -68,7 +68,6 @@ int main(int argc _U_, char *argv[] _U_) {
   if (!CU_add_test(pSuite, "pq", test_nghttp2_pq) ||
       !CU_add_test(pSuite, "pq_update", test_nghttp2_pq_update) ||
       !CU_add_test(pSuite, "pq_remove", test_nghttp2_pq_remove) ||
-      !CU_add_test(pSuite, "pq_increase_key", test_nghttp2_pq_increase_key) ||
       !CU_add_test(pSuite, "map", test_nghttp2_map) ||
       !CU_add_test(pSuite, "map_functional", test_nghttp2_map_functional) ||
       !CU_add_test(pSuite, "map_each_free", test_nghttp2_map_each_free) ||
diff --git a/tests/nghttp2_pq_test.c b/tests/nghttp2_pq_test.c
index 76278125..c37b156a 100644
--- a/tests/nghttp2_pq_test.c
+++ b/tests/nghttp2_pq_test.c
@@ -224,34 +224,3 @@ void test_nghttp2_pq_remove(void) {
 
   nghttp2_pq_free(&pq);
 }
-
-void test_nghttp2_pq_increase_key(void) {
-  nghttp2_pq pq;
-  node nodes[10];
-  int ans_key1[] = {1, 2, 3, 3, 4, 5};
-  int ans_val1[] = {1, 2, 0, 3, 4, 5};
-  int ans_key2[] = {0, 1, 2, 3, 4, 6};
-  int ans_val2[] = {0, 1, 2, 3, 4, 5};
-
-  nghttp2_pq_init(&pq, node_less, nghttp2_mem_default());
-
-  push_nodes(&pq, nodes, 6);
-
-  nodes[0].key = 3;
-  nghttp2_pq_increase_key(&pq, &nodes[0].ent);
-
-  check_nodes(&pq, 6, ans_key1, ans_val1);
-
-  nghttp2_pq_free(&pq);
-
-  nghttp2_pq_init(&pq, node_less, nghttp2_mem_default());
-
-  push_nodes(&pq, nodes, 6);
-
-  nodes[5].key = 6;
-  nghttp2_pq_increase_key(&pq, &nodes[5].ent);
-
-  check_nodes(&pq, 6, ans_key2, ans_val2);
-
-  nghttp2_pq_free(&pq);
-}
diff --git a/tests/nghttp2_pq_test.h b/tests/nghttp2_pq_test.h
index 7a8afe25..2936174e 100644
--- a/tests/nghttp2_pq_test.h
+++ b/tests/nghttp2_pq_test.h
@@ -28,6 +28,5 @@
 void test_nghttp2_pq(void);
 void test_nghttp2_pq_update(void);
 void test_nghttp2_pq_remove(void);
-void test_nghttp2_pq_increase_key(void);
 
 #endif /* NGHTTP2_PQ_TEST_H */