PURPOSE: To obtain an effective extended input device in an object constituted in a small design, by disposing the extended input contact wire for key input detection parallel to the key input contact wire.

CONSTITUTION: One of the three contact wires 13 of switches 3 to 5 consisting of a key 10, a rubber 11 with conductive rubber 12, and three contact wires 13 is used as an extended input contact wire for key input detection 2, and is wired to an electronic pocket calculator IC 1. Inside the electronic pocket calculator IC 1, the extended input contact wire for key input detection is designed to always clear the timer time and start the timer counting from zero time every time a key input is made. In this setting, when one of the switches 3 to 5 is pressed, simultaneously with key input of CL, +, 8, etc., the same signal will be inputted into the extended input contact for key input detection 2, so that the timer may be extended.