A lighting system includes: a wireless communication device that transmits a test signal; luminaires that measure a signal strength of the test signal upon receipt and transmit signal strength information on the signal strength to the wireless communication device; and a determining unit that determines a condition of the lighting system based on the signal strength or the signal strength information. The determining unit: determines the condition of the lighting system to be acceptable upon confirming transmission of the signal strength information by all luminaires and unacceptable upon failing to confirm transmission of the signal strength information by at least one luminaire; or determines the condition of the lighting system to be acceptable when each signal strength measured by all luminaires exceeds a reference value and unacceptable when the signal strength measured by at least one luminaire is less than or equal to the reference value.