Substrate processing apparatus and substrate processing method

A substrate processing method for processing a substrate, comprising:

• a step (a) of holding a substrate by a substrate holding portion provided on a spin base;
• a step (b) of supporting the substrate held by the substrate holding portion in the step (a) by a substrate support portion provided on the spin base;
• a step (c) of rotating the substrate by rotating the spin base around a rotation axis in a vertical direction;
• and
• a step (d) of supplying a processing liquid on an upper surface of the substrate rotated in the step (c), wherein
• the substrate support portion comprises an inner portion that vertically overlaps the substrate held by the substrate holding portion in the step (a), and
• an upper end of the substrate support portion is on a side below an upper surface of an overlapping portion of the substrate held by the substrate holding portion that overlaps the inner portion in the vertical direction.