A substrate processing apparatus (1) has a first polishing unit (400A) and a second polishing unit (400B) for polishing a peripheral portion of a substrate. Each of the two polishing units (400A, 400B) includes a bevel polishing device (450A, 450B) for polishing a peripheral portion of a substrate and a notch polishing device (480A, 480B) for polishing a notch of a substrate. The substrate processing apparatus (1) has a maintenance space (7) formed between the two polishing units (400A, 400B). The bevel polishing devices (450A, 450B) in the two polishing units (400A, 400B) face the maintenance space (7) so as to be accessible from the maintenance space (7).