An electromagnetic wave detecting apparatus is provided with: a plurality of detecting devices each of which is configured to detect an electromagnetic wave; a voltage applying device configured to apply bias voltage to each of the plurality of detecting devices; an obtaining device configured to obtain a detection signal outputted from each of the plurality of detecting devices; and a setting device configured to set acquisition timing of the detection signal for each of the plurality of detecting devices, on the basis of the bias voltage, which is applied to each of the plurality of detecting devices, and the detection signal of each of the plurality of detecting devices.