This endoscope system 1, which acquires an image captured inside a subject, is provided with: a detection device 50 that detects electromagnetic waves radiated in accordance with a coil driving signal and that outputs a response signal a coil 40 that radiates electromagnetic waves toward the detection device by using the applied coil driving signal a transmission line 60 through which signals are transmitted between an oscillator and the coil and an insertion shape calculation unit that obtains the distance between the coil and the detection device on the basis of an output timing at which the coil driving signal is outputted from the oscillator and a reception timing at which the response signal from the detection device is received, and that calculates an insertion shape of an insertion part on the basis of the distance.
