A power seat drive device (100) comprises a sense electrode (10) provided in the back portion (102) of a power seat (101), and a controller (20) operative to control movement of the power seat (101) based on a sense signal from the sense electrode (10). The controller (20) decelerates the speed of movement and provides a warning sound when the proximity distance between the sense electrode (10) and a human body (108) becomes short so as to exceed a decision voltage (Vth1). In addition, the controller stops the movement of the power seat (101) when the proximity distance becomes much shorter so as to exceed a decision voltage (Vth2).