human body to the electric fabrics based on such electric current. The determining means compares the combined pattern of the outputs from the human body approach detecting means with the previously stored patterns, determines whether the occupant is sitting on the seat and determines the physique of the occupant sitting on the seat.
Since the presence and absence and the physique of the occupant sitting on the seat are determined based on the approach of the human body, which is a dielectric to the plurality of electrode fabrics, it is possible to carry out the precise determination irrespective of a variation in hardness of a seat skin member caused by a variation in temperature, a variation in sitting attitude of the occupant, a variation in reclining angle of theelectrode fabrics embedded in a central portion of a seat back of a seat in an automobile, at least one second electrode fabric embedded in a side of the seat back of the seat, an electric field generating means for generating an electric field around the first and second electrode fabrics, a human body approach detecting means for detecting the approach of a human body to the first and second electrode fabrics, based on electric current flowing from the electric field generating means to the first and second electrode fabrics, a first determining means for determining whether a sitting height of an occupant sitting on the seat is equal to, or smaller than, a reference value by comparing a combined pattern of outputs from the human body approach