diff --git a/sys/pc98/cbus/sio.c b/sys/pc98/cbus/sio.c
index 7e0c080f83bf..f06363d552b0 100644
--- a/sys/pc98/cbus/sio.c
+++ b/sys/pc98/cbus/sio.c
@@ -140,6 +140,7 @@
 #endif /* PC98 */
 
 #include <sys/param.h>
+#include <sys/bus.h>
 #include <sys/systm.h>
 #include <sys/reboot.h>
 #include <sys/malloc.h>
diff --git a/sys/pc98/pc98/sio.c b/sys/pc98/pc98/sio.c
index 7e0c080f83bf..f06363d552b0 100644
--- a/sys/pc98/pc98/sio.c
+++ b/sys/pc98/pc98/sio.c
@@ -140,6 +140,7 @@
 #endif /* PC98 */
 
 #include <sys/param.h>
+#include <sys/bus.h>
 #include <sys/systm.h>
 #include <sys/reboot.h>
 #include <sys/malloc.h>