Abstract: An inspection apparatus is disclosed which is adapted to accurately detect an irradiated position on a target board which is irradiated with a beam, to thereby inspect deformation of a pipe such as a sewer or the like. A laser beam emitting unit (3) is arranged on one end side of a sewer (1). The laser beam emitting unit (3) is so adjusted that a laser beam (15) is impinged on a target board (11) of a target vehicle (9) traveling from the other end side of the pipe toward the laser beam emitting unit (3). The target board (11) is provided thereon with a plurality of phototransistors (13), whereby the irradiated position is detected depending on electric signals generated by the phototransistors.