An imager apparatus is provided. The imager apparatus includes: a housing that stores a lens device with an imaging lens exposed to the front surface facing a subject; and a lens cover attached to the housing, being movable between a first position covering the imaging lens and a second position opening the same. The lens device includes a lens barrel supporting a lens system including the imaging lens in a fixed and/or movable manner, whose forefront part protrudes forward compared with the imaging lens. A stepped portion corresponding to a level difference between the forefront part of the lens barrel and the imaging lens is provided at part of the front surface of the housing, where the lens device is stored. A peaked portion protruding into the stepped portion to eliminate a gap between the lens cover and the housing is provided on the lens cover.