Abstract: A tablet determining method and an apparatus therefor capable of accurately determining ingredients of a multi-layer tablet without breaking the tablet. A multi-layer tablet is lighted from light sources, an area of the side surface of the tablet on which a boundary line between the layers appears is detected by image processing, an area of the side surface of at least one of the layers of the tablet which are separated by the boundary line is detected by image processing, and data obtained by the image processing and data on the total weight of the tablet are used for determining the layer by processing.