An inspection method for a pillar-shaped honeycomb filter having a honeycomb-shaped first end face and a honeycomb-shaped second end face, including:



allowing gas containing fine particles to flow into the first end face;
imaging the entire second end face covered with the sheet-like light using a camera while the gas that has flowed into the first end face flows out of the second end face through the filter, and generating an image of the entire second end face covered with the sheet-like light;
selecting an inspection area of the second end face and measuring information concerning a sum of luminance of all pixels in the inspection area; and
determining quality of the filter based on at least the information concerning the concentration of the fine particles in the gas before the gas flows into the first end face and the information concerning the sum of luminance.