To prevent intrusion of a lightning surge from an alternating current side to a direct current side, and protect the direct current side from the lightning surge more strongly.

A direct current side protector 80 is mounted on a board 81, an alternating current side protector 90 is mounted on a board 91, and they are separated. The direct current side protector 80 is provided with a surge absorber 73, B terminals B+ and B- connected to the surge absorber 73, choke coils 74 and 75, L terminals L+ and L-connected to the B terminals via the choke coils 74 and 75, a three pole arrester tube 77 connected to the L terminals L+ and L- via varistors 76 and 78, choke coils 71 and 72, M terminals M+ and M-connected to the B terminals via the choke coils 71 and 72, choke coils 82 and 83, and ME terminals ME+ and ME- connected to the B terminals via the choke coils 82 and 83. An electronic grade crossing controller is connected to the ME terminals.