1. A human body detection sensor for detecting a detection target provided with: an imaging unit that includes an imaging element in which pixels are arranged in a one-dimensional manner or in a two-dimensional manner; and a light-emitting unit disposed with an offset from this imaging unit, in which the imaging unit receives reflected light generated by light projected by this light-emitting unit, comprising: a specular reflection decision unit that decides whether or not the reflected light is specularly-reflected light; and a continuation decision unit that decides whether or not a state in which the detection target exists is ongoing, wherein, when the reflected light is decided to be specularly-reflected light during the detection of the detection target, a determination indicating detection is kept if the result of the decision by the continuation decision unit indicates that the state is ongoing, and a determination indicating non-detection is made if the result of the decision by the continuation decision unit indicates that the state is not ongoing, wherein the continuation decision unit is configured to detect a temporal change of the reflected light so as to decide the presence of a moving object and decide that the state in which the detection target exists is ongoing when the continuation decision unit decides that the moving object is present.