Abstract: A charged-particle detecting device 108, 108a, 108b, 108c, 108d, 108e, 108f, 108g or a radiation detecting device 203 detects charged particles or radiation as a detection target. These detection devices are each provided with: a scintillator 109 provided with a fluorescent layer 109a that converts the detection target into light 112; a light detector 111, 111b that detects the light 112 emitted from the scintillator 109; a light guide 110, 117 provided between the scintillator 109 and the light detector 111, 111b; and a blocking part 113, 114 that blocks a portion of the detection target incident on the scintillator 109 or the light emitted from the scintillator 109.