A substrate processing apparatus and a substrate processing method, with which a resist can be removed satisfactorily from the substrate and a processing solution used for removing the resist can be recycled, are provided. The substrate processing apparatus includes: a substrate holding means holding a substrate; a peroxosulfuric acid generating means generating a peroxosulfuric acid using sulfuric acid; a mixing means mixing the peroxosulfuric acid generated by the peroxosulfuric acid generating means and sulfuric acid of higher temperature and higher concentration than the sulfuric acid used in the peroxosulfuric acid generating means; and a discharging means discharging, toward the substrate held by the substrate holding means, the mixed solution of the peroxosulfuric acid and the sulfuric acid mixed by the mixing means as a processing solution for removing a resist from the substrate.