To provide a switch operation detection device that can be made compact.

An engine switch 1 includes a switch knob 2 to be operated and in the switch knob 2, a ferrite core 3 is buried which is associated with displacement accompanying an operation of the switch knob 2. Then a coil antenna 4 is provided surrounding the ferrite core 3, and a current flows to the coil antenna 4. In a stage before the operation of the switch knob 2, the switch knob 2 is at an origin position, and the ferrite core 3 is arranged in the center of the coil antenna 4. When the switch knob 2 is pressed, the ferrite core 3 is present at a position off the center of the coil antenna 4. The current flowing to the coil antenna 4 varies as the switch knob 2 is operated. The operation of the switch knob 2 is detected based upon the variation of the current.