A human body detection sensor that has reduced detection error and improved detection performance is provided. In the human body detection sensor (1), reflected light generated in response to light cast by a light-emitting section (25) is received by an imaging section (26), and an object to be detected is detected, the human body detection sensor comprising: centroid identifying means (322) for identifying the centroid position of reflected light within a light reception area; first determination means (323A) for determining whether the centroid position falls within a detection area; second determination means (323B) for determining, in accordance with the result of processing a threshold value for the pixel value of a centroid pixel, the suitability of the extent to which light is received by the centroid pixel; and detection output means (324) for outputting a detection signal indicating that an object to be detected has been detected when both the first and second determination means (323A, B) have made an affirmative determination.