An illumination system includes a light source device configured by an excitation light source, a light guiding member and a wavelength converter that are connected in order, and an operation check device. The system further includes: a connector configured to directly and physically connect the operation check device to a light signal emitting end which includes the wavelength converter; a detector configured to detect a light signal emitted from the light signal emitting end when the light signal emitting end and the operation check device are connected by the connector; and an operation determiner configured to determine the operations of the excitation light source, the light guiding member, and the wavelength converter by a detection result in the detector.