A can body inspection apparatus which prevents a drop in resistance to noise while enabling high speed inspection is provided. It is comprised of a light source control means (21, 22) for turning on the light source unit a predetermined number of times of two times or more at predetermined timings at which light can be taken in by the light-detection unit through the open end face of the can body W which is moving along the path of conveyance W, a detection signal integrating means 23 for integrating signal values based on the detection signal which is output from the light-detection unit 15 due to on operations of the light source unit 10, and a condition judging means 24 for using an integrated value which is obtained by the detection signal integrating means 23 as the basis to judge the condition of the can body.