To provide a game controller with which a detection means for detecting an insertion degree of a length can be simplified. A game controller includes a controller body to which is attached a flexible member having formed therein an insertion hole into which a length is inserted, a laser transmitter/receiver that is installed on an outer periphery of the controller body and measures a distance with respect to a base surface of the length by transmission and reception of a wave to detect an insertion degree of the length inserted from the insertion hole, and a wiring cable and a control circuit that output the insertion degree of the length detected by the laser transmitter/receiver.