An explosion-proof electronic device includes: a first circuit board provided with a first connector on one surface thereof; and a second circuit board provided with a second connector on a surface facing the one surface of the first circuit board, the second connector being fit to the first connector. A packing is attached to a position on the second connector which is away from the surface of the second circuit board, surrounds the outer circumference of the second connector, and extends toward the first circuit board to form a closed space including an interface between the first and second connectors. The space between the first and second circuit boards is filled with a filler with the first and second connectors fit to each other.