Provided is a specimen staining apparatus that includes a gap-forming member arranged to form a gap having a thickness that induces capillary action, the gap being formed above a mounting surface of a slide glass having a specimen mounted thereon; and a chemical solution supply unit that supplies a chemical solution for staining the specimen to the gap between the gap-forming member and the mounting surface so that the chemical solution spreads within the gap due to capillary action and is evenly supplied to the specimen placed on the mounting surface.