A tablet inspection device according to the present embodiment has a differential image generation unit for generating a horizontal differential image that is a horizontal differential image of a photographed image of a tablet and a vertical differential image that is a vertical differential image of the photographed image; an inner product image generation unit for generating an inner product image based on the inner product of a reference image having a vector in a direction tangential to a concentric circle around the center of the tablet, the horizontal differential image, and the vertical differential image; a logical conjunction image generation unit for generating a logical conjunction image based on the logical conjunction of a vicinity mask masking the vicinity of the tablet and the inner product image; a threshold image generation unit for generating a threshold image by binarizing the logical conjunction image on the basis of a prescribed threshold; and a determination unit for determining the presence of defects in the tablet on the basis of the results of labelling processing of the threshold image.