A substrate processing apparatus flows a propagation liquid for propagating ultrasonic vibrations, and controls the flow rate thereof. The ultrasonic vibrations are scattered by the flow of the propagation liquid, so that a concentrated impact of the ultrasonic vibrations given on a substrate is relieved. The substrate processing apparatus can increase the output power of ultrasonic vibrations by controlling the flow rate of the propagation liquid while preventing a fine pattern formed on the substrate from stripping or falling down.