Weight sensor device

The present invention provides a weight sensor device for detecting a weight of an occupant seated on a seat having a seat frame and a cushion. The device has a sensing wire (70) displaced downward in the seat frame as the cushion is deformed due to the weight of the occupant when the occupant is seated on the seat and a variable resistor (50) for converting a displacement of the sensing wire into an electric signal indicative of the weight of the occupant.