It is intended to provide a substrate processing apparatus capable of reliably informing a running state of the apparatus. The substrate processing apparatus 100 having a signal indicator for indicating the running state, including a signal indicator 306 capable of setting at least one operation condition under which the signal indicator 306 operates as well as of operating under any one of a plurality of operation conditions and a display unit 314 capable of displaying that a cause of the operation is any one of the operation conditions during the operation of the signal indicator 306.