A weight inspection apparatus includes a weight obtaining unit, an irradiation unit, a detection unit and an estimated weight calculation unit. The weight obtaining unit is configured to obtain an actual weight of an inspection target object. The irradiation unit is configured to irradiate the inspection target object with energy waves. The detection unit is configured to detect the energy waves irradiated at the inspection target object. The estimated weight calculation unit is configured to calculate an estimated weight of the inspection target object based on a result of detection by the detection unit. The deviation amount calculation unit is configured to calculate a difference between the actual weight obtained by the weight obtaining unit and the estimated weight obtained by the estimated weight calculation unit.