A hatching egg inspection apparatus includes a loader unit (2), an inspection unit (3) for determining the viability or the like as to whether a hatching egg is an unfertilized egg or a growth-stopping egg, a rejection unit (4) for rejecting a hatching egg determined to be an unfertilized egg or the like, and an unloader unit (5) for sending a hatching egg toward the next step. The inspection unit (3) is provided with a light emitting unit (11) for emitting prescribed light toward the hatching egg, a cap attachment unit (16) through which the light having been emitted to the hatching egg and having transmitted through the hatching egg passes, and a light receiving unit (22) for receiving the light that has passed through the cap attachment unit (16). The cap attachment unit (16) includes a cylindrical cap (20) coming into contact with the hatching egg, and a plate (17) to which the cap (20) is attached. The cap attachment unit (16) is slidably held by a guide rail (21).
