<p>A method for manufacturing an infrared sensor having: a step for forming a thermopile support layer in a first area; a step for forming a thermopile (24) on the upper surface thereof; a step for thereafter forming a circuit element in a second area; a step for covering the first and second areas to form an upper-part layer (41); a step for digging the upper-part layer (41) down to an intermediate point; a step for forming an etching hole (38) by further digging the upper-part layer (41) down; and a step for forming a sensor unit (2) by etching a portion of a semiconductor substrate (1) via the etching hole (38) to suspend the thermopile support layer and the thermopile (24) over the semiconductor substrate (1). The upper surface (2u) of the sensor part (2) is positioned lower than the upper surface of an upper-part layer (41u) in the second area.</p>
