A substrate processing apparatus (1) includes first and second polishing units (70A, 70B) for polishing a peripheral portion of a substrate (W), a primary cleaning unit (100) for cleaning the substrate (W), a secondary cleaning and drying unit (110) for drying the substrate (W) cleaned in the primary cleaning unit (100), and a measurement unit (30) for measuring the peripheral portion of the substrate (W). The measurement unit (30) includes a mechanism for measurement required for polishing in the first and second polishing units (70A and 70B), such as a diameter measurement mechanism, a cross-sectional shape measurement mechanism, or a surface condition measurement mechanism.