A substrate processing apparatus includes: a holding unit holding a substrate; a rotation driving unit rotating the substrate held on the holding unit; a moving mechanism moving the holding unit between a delivery position and an edge exposure position; an exposure unit provided on the edge exposure position side and exposing an edge portion of a coating film above the substrate held on the holding unit; an image capturing unit provided on the edge exposure position side and above the exposure unit and capturing an image of the substrate held on the holding unit; and a direction change unit changing a direction of an optical path formed between the substrate held on the holding unit and the image capturing unit. The direction change unit includes a first reflecting mirror, a second reflecting mirror, and a third reflecting mirror.