PYROELECTRIC INFRARED RADIATION SENSOR

PROBLEM TO BE SOLVED: To provide a pyroelectric sensor wherein airtightness of the inside of the sensor is ensured and sufficient electromagnetic shielding property from a low frequency to a high frequency can be obtained, in a pyrolectric infrared radiation sensor without using a stem. SOLUTION: This pyroelectric infrared radiation sensor is equipped with a circuit board 7 mounting a pyroelectric element 3 outputting an electric signal in accordance with receiving infrared radiation dose and an FET 5, a power source terminal, an output terminal and a ground terminal fixed on the circuit board 7, and a cap 2 made of metal having a window to which an infrared transmission filter 1 for taking infrared radiation in the pyroelectric element 3 is fixed. The surface of the circuit board 7 inserted in the cap 2 which surface is opposite to the surface mounting the pyroelectric element 3 and the FET 5 is covered with a conductor foil. Ground wiring of the circuit board 7, the ground terminal, the conductor foil and the cap are electrically connected. The gap between the cap in the circuit board periphery and the circuit board 7 is sealed with sealing material.