The object of the invention is to provide a seating load detecting device which can correctly detect a eating state of an occupant of a seat even when the device is arranged on a vehicle seat cushion with bending.
The seating load detecting device includes a band shaped first film formed by a plurality of portions to be contacted, each portion being separated with a distance from each other forming a pressure sensitive switch for detecting a seating state of an occupant of a seat and a switch connecting wiring connecting the plurality of portions to be contacted, a band shaped second film disposed facing to the first film and formed by a plurality of portions to contact forming the pressure sensitive switch and contacting with or separating from the corresponding plurality of portions to be contacted and a partition member disposed between the first and the second films and formed with a plurality of penetration holes positioned opposite to the plurality of pressure sensitive switches and an air passage communicating with the plurality of penetrating holes and exposed to the atmosphere. The first and the second films, between which the partition member is interposed are attached to a seating surface of the seat under the films being bent, and the partition member includes a relief hole provided between a bent portion formed by the first and the second films when attached to the seating surface of the seat and one of the plurality of pressure sensitive switches positioned closest to the bent portion for absorbing a strain.