To prevent a fault from occurring because a stroboscopic device gets wet with water.

A water-proof and insulating ink layer 42 is formed on a stroboscopic base plate 23 where a circuit part such as a capacitor charged at high voltage so as to make a stroboscope emit light is soldered. The layer 42 is formed as a thick-film printing layer by a screen printing (silk printing). The whole of a resist film on a wiring pattern where voltage gets high at the time of charging the stroboscope is covered with the layer 42 so as to prevent the water adhering to the base plate 23 from penetrating the resist film and reaching the wiring pattern.