To provide a blind washing apparatus which makes it possible to wash slats without bending them has a small size for contributing to saving of installation space, and its washing method.

This blind washing apparatus S comprises a wash liquid reservoir 1, a housing body 2, a pump 3, and a heater 4. The housing body 2 is composed of a frame 20 and shielding walls 21 surrounding the frame 20. The frame 20 consists of pillars 200, 201, 202, and 203, and a setting base 204 as a foundation. A blind mount 22, on which a blind is placed, is formed inside, surrounded by those pillars 200, 201, 202, and 203. A plurality of injection ports 23, ... are provided on one side of the pillar 200 and the pillar 201. A blind is vertically placed on the blind mount 22, so that its width side can become upright, and each slate can be vibrated or swung.