The present disclosure intends to provide an optical signal from an ONU according to a desired service usage state without using the ONU and an OLT. A simulated signal light generation apparatus 10 according to the present disclosure is a simulated signal light generation apparatus 10 for simulating an uplink signal light generated in an optical network unit (ONU) in a passive optical network (PON), and the apparatus includes a usage state control unit 11 that sets a service usage state of the ONU, a signal generation unit 12 that generates an uplink signal frame according to the usage state set by the usage state control unit 11, and an electrical/optical conversion unit 13 that converts an electrical signal from the signal generation unit 12 into an optical signal, and the optical signal from the electrical/optical conversion unit 13 is repeatedly transmitted to an optical fiber core 22.