According to the disclosed substrate processing apparatus, a first bowl is located to correspond to a substrate, and a first chemical solution supply module supplies a first chemical solution while a support module rotates at a first speed, and a second bowl is located to correspond to the substrate, and a second chemical solution supply module supplies a second chemical solution at a first flow rate while a support module rotates at a second speed equal to or smaller than the first speed, and the second bowl is located to correspond to the substrate, and the second chemical solution supply module does not supply the second chemical solution or supplies the second chemical solution at a second flow rate smaller than the first flow rate while the support module rotates at a third speed smaller than the second speed.