There is disclosed an inspection device of a plugged honeycomb structure in which a plugged honeycomb structure is an inspection target, and the inspection device comprises a light source which illuminates one end face of the plugged honeycomb structure as the inspection target; a camera-side lens which condenses light emitted from the light source to the one end face, transmitted through plugged portions of the plugged honeycomb structure and radiated from the other end face; a camera which receives the light condensed by the camera-side lens; and an image processor which processes an image of the light received by the camera to display the contrast of the light transmitted through the plugged portions of the plugged honeycomb structure.