An example game controller includes L and R buttons provided in both left and right end portions on an upper surface of a housing and ZL and ZR buttons provided to sides of the L and R buttons closer to a back surface of the game controller. The ZL/ZR button includes a protruding portion protruding in the direction of the back surface of the game controller and the direction of a side surface of the game controller. This makes it possible to increase the area of an upper surface of a key top of the ZL/ZR button and improve the operability of the ZL/ZR button.