Provided is an endoscopic system that can accurately determine a transmission state on the basis of a bit error rate and light reception sensitivity, and thus is capable of coping quickly even when there is an anomaly in the transmission state. This endoscopic system 1 is characterized by being provided with: an imaging element 10 that images a subject; a first photoelectric element 11 that converts test data and an imaging signal output from the imaging element 10 into an optical signal and outputs said optical signal; an optical fiber 13 that transmits the optical signal output from the first photoelectric element 11; and an information processing device 3 that has a second photoelectric element 20, which receives the optical signal transmitted by the optical fiber 13, a light intensity measurement unit 22, which measures the reception sensitivity of the test data which has been converted into an electrical signal by the second photoelectric element 20, a bit error rate measurement unit 26, which measures the bit error rate of the test data, and a determination unit 27, which determines the transmission state of the test data on the basis of the reception sensitivity and the bit error rate.