An infrared sensor includes a circuit board, at least two support portions, a FET element and a pyroelectric element. The circuit board has an upper principal surface formed with plural electrodes. Each of the support portions has an upper surface, a lower surface, an upper conductive pattern formed on the upper surface and a lower conductive pattern formed on the lower surface. The upper conductive pattern is electrically connected with the lower conductive pattern. The lower conductive pattern is connected to an electrode of the upper principal surface of the circuit board. The FET element is located between the at least two support portions and arranged on the upper principal surface of the circuit board. The pyroelectric element is electrically connected with the upper conductive patterns of the support portions, and is supported by the support portions so as to be located above the FET element.