diff --git a/src/IPStackSimulator.cc b/src/IPStackSimulator.cc
index af854a08..693f77fd 100644
--- a/src/IPStackSimulator.cc
+++ b/src/IPStackSimulator.cc
@@ -2,6 +2,7 @@
 
 #include <stdint.h>
 #include <netinet/in.h>
+#include <event2/buffer.h>
 #include <event2/bufferevent.h>
 #include <event2/listener.h>
 
@@ -16,8 +17,6 @@
 #include <phosg/Network.hh>
 #include <phosg/Random.hh>
 #include <phosg/Time.hh>
-#include <event-async/Base.hh>
-#include <event-async/Buffer.hh>
 
 #include "IPFrameInfo.hh"
 #include "DNSServer.hh"
diff --git a/src/IPStackSimulator.hh b/src/IPStackSimulator.hh
index f19a3783..87936b03 100644
--- a/src/IPStackSimulator.hh
+++ b/src/IPStackSimulator.hh
@@ -5,8 +5,6 @@
 #include <string>
 #include <phosg/Process.hh>
 #include <phosg/Filesystem.hh>
-#include <event-async/Task.hh>
-#include <event-async/Base.hh>
 
 #include "IPFrameInfo.hh"
 #include "Server.hh"