A substrate processing method includes a substrate holding step of disposing a substrate at a position surrounded by a plurality of guards which have a first guard and a second guard in a plan view and of holding the substrate horizontally, a substrate rotating step of rotating the substrate around a vertical rotation axis which passes through a central portion of the substrate, a hydrophobic agent supplying step of supplying to the upper surface of the substrate in a rotating state a hydrophobic agent which is a liquid for hydrophobizing the upper surface of the substrate, a low surface-tension liquid supplying step of supplying the low surface-tension liquid to the upper surface of the substrate in the rotating state in order to replace the hydrophobic agent on the substrate by the low surface-tension liquid lower in surface tension than water, a first guard switching step of switching a state of the plurality of guards to a first state in which the first guard receives a liquid scattered from the substrate by moving at least one of the plurality of guards up and down before start of the low surface-tension liquid supplying step, and a second guard switching step of switching a state of the plurality of guards from the first state to a second state in which the second guard receives a liquid scattered from the substrate by moving the plurality of guards up and down during execution of the low surface-tension liquid supplying step.