SEAT OCCUPANCY DETECTION DEVICE

A seat occupancy detection device (20) includes: a membrane switch (10) that forms a seat occupancy detection section (40) on a seat occupancy surface (S) of a seat cushion (2); and a seat occupancy determination device (50) that determines a seat occupancy state of an occupant with respect to the seat cushion, based on an ON/OFF state of the membrane switch, wherein a plurality of detection regions (±1, ±2, ²1, ²2) are set on the seat occupancy detection section by dividing the seat occupancy detection section in a frontward-rearward direction and in a width direction of a seat, and wherein the membrane switch is configured to enter an ON state in a case where pressure-sensitive switch units (SW, SW1, SW2, SW3, SW4) arranged in two detection regions, respectively, which are adjacent in the frontward-rearward direction of the seat, simultaneously enter a conduction state.