A gate apparatus (10) includes first and second housing (110a, 110b) defining a passage (30) through which a person passes, a recessed portion (120) being provided on a lateral surface (112), facing the passage (30), of at least one of housings being the first housing (110a) and the second housing (110b), a first antenna (130) being provided in the recessed portion (120), and a radio wave absorbing material (142, 144) being provided in a region (an inner lateral surface 122, and a region 124 of the lateral surface 112) of the lateral surface (112) providing the recessed portion (120) being located closer to the passage (30) side than the first antenna (130).