A substrate processing method includes a phosphoric acid processing step of supplying a phosphoric acid aqueous solution, which contains silicon and has a silicon concentration lower than a saturation concentration, to a front surface of a substrate, a liquid volume reducing step of reducing a volume of the phosphoric acid aqueous solution on the substrate, after the phosphoric acid processing step, and a rinse replacing step of supplying a rinse liquid having a temperature lower than that of the phosphoric acid aqueous solution supplied to the front surface of the substrate in the phosphoric acid processing step to the front surface of the substrate covered with the phosphoric acid aqueous solution at least partially, after the liquid volume reducing step.