To reduce the occurrence of wrong operation even with areas for detecting a touch by a finger set adjacently with one another.

A capacitive touch key device 10 of the present invention includes: a substrate 18 having a GND layer 17 therein; plural keypads 11 placed on one face of the substrate 18 and forming flat plate capacitors C by facing the GND layer 17; a sensor 12 for detecting change in capacitance produced in the flat plate capacitors formed by the plural keypads 11; and separation structures (including GND patterns 14a) provided on the boundaries between the plural keypads 11 and having conductivity.