A substrate processing apparatus according to an embodiment includes: a liquid supplier configured to supply a processing liquid to a surface of a substrate; a temperature detector configured to detect a surface temperature of the substrate supplied with the processing liquid by the liquid supplier; a temperature monitor configured to determine whether or not the surface temperature detected by the temperature detector has reached a predetermined temperature; and a controller configured to cause the liquid supplier to stop supplying the processing liquid when the temperature monitor determines that the surface temperature has reached the predetermined temperature.