A circuit device is provided which can be manufactured at reduced costs and which is highly reliable. The circuit device includes a Sensor area formed on part of a semiconductor substrate, a circuit area formed around the sensor area on the semiconductor substrate to process electric signals produced at the sensor area, and a sealring disposed between the sensor area and the circuit area. The sealring is disposed between the outer periphery of the sensor area and the inner periphery of the circuit area to surround the sensor area. In the circuit device, the sealring prevents water or moisture from infiltrating from the sensor area into the circuit area.