To reduce a contact area between a sensor element and sensor element supports, and to thereby reduce radiation of heat of an infrared ray at the minimum, by forming the sensor element supports in a spherical shape, in a pyroelectric infrared sensor.

A sensor element 3 and sensor element supports 8, and also the sensor element supports 8 and a circuit board 5 are equally fixed each other by a conductive adhesive or the like. The spherical sensor element supports 8 are fixed on prescribed positions of the circuit board 5 by the conductive adhesive, and thereafter the conductive adhesive is coated on the upper parts of the spherical sensor element supports 8, and the sensor element 3 is placed on the spherical sensor element supports 8, and the conductive adhesive is hardened. In order to prevent radiation of heat from adhesion parts, an anisotropic adhesive capable of securing conductivity in the pressing direction is preferable as the conductive adhesive. In order to prevent radiation of heat, as material of the sensor element supports 8, the material having low thermal conductivity, for example, the material formed by forming a metal thin film on the surface of a resin, is preferable, on condition that conduction of the surface is secured.