occupant sits on the seat, the body of the occupant having a high dielectric constant as compared with that of air approaches the first and second electrode fabrics embedded in the seat back and hence, the electric current flowing from the electric field generating means to the electric fabrics is increased. When the electric current flowing to the electrode fabrics is increased, the human body approach detecting means detects the approach of the human body to the electrode fabrics, based on such electric current.
The first determining means compares the combined pattern of those outputs from the human body approach detecting means which correspond to the plurality of first electrode fabrics with the previously stored pattern, and determines whether the sitting height of the occupant sitting on the seatthe predetermined value. When the occupant sits on the seat, the electric current flowing from the electric field generating means to the electrode fabric is increased, because the human body having a high dielectric constant as compared with that of air approaches the electrode fabric embedded in the side of the seat back. When the electric current flowing to the electrode fabric is increased, the human body approach detecting means detects the approach of the human body to the electrode fabric, based on the electric current. The second determining means determines whether the body of the occupant on the seat is leaning sideways, based on the output from the human body approach detecting means.
When the first determining means determines that the weight of the occupant is equal to,