Abstract: Operation detection device having high detection accuracy based on reduced effects of noise is provided. Operation detection device includes electrostatic sensor, drive circuit to output a drive signal to electrostatic sensor to detect operator's operation on electrostatic sensor, and control unit to determine presence or absence of operation based on output value of electrostatic sensor, and to control drive waveform of drive signal. Control unit controls drive waveform according to a cycle that is a predetermined period of time including both detection period in which detection of operation is performed and non-detection period in which detection of operation is not performed. The drive waveform has a shape that is based on periodic function that repeats a constant pattern for an entirety of the cycle. The control unit changes the phase of the drive signal in the detection period by controlling a property of the drive waveform in the non-detection period.