An explosion-proof electronic device comprising: a first circuit board provided with a first connector on one surface thereof; 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; characterized in that the explosion-proof electronic device further comprises: a packing which 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 (4, 5), and a filler filling a space between the first and second circuit boards (1, 2) with the first and second connectors (4, 5) fit to each other, wherein the packing includes: a supporting portion which is attached at a predetermined distance away from the second circuit board on the side surface of the second connector and surrounds the outer circumference of the second connector; and a wall portion which is attached to the supporting portion and extends toward the first circuit board, wherein a length of the wall portion, measured from a first end of the wall portion on the second circuit board side to a second end on the first circuit board side is greater than the distance between the position of the first end and the surface of the first circuit board when the first and second connectors are fit to each other, wherein the second end of the wall portion comes into close contact with the one surface of the first circuit board by being pressed by the first circuit board, and wherein the wall portion is elastically deformed in a direction of separation from the interface between the first and second connectors (4, 5). a first circuit board provided with a first connector on one surface thereof; 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; characterized in that the explosion-proof electronic device further comprises: a packing which 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 (4, 5), and a filler filling a space between the first and second circuit boards (1, 2) with the first and second connectors (4, 5) fit to each other, a packing which 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 (4, 5), and a filler filling a space between the first and second circuit boards (1, 2) with the first and second connectors (4, 5) fit to each other, wherein the packing includes: a supporting portion which is attached at a predetermined distance away from the second circuit board on the side surface of the second connector and surrounds the outer circumference of the second connector; and a wall portion which is attached to the supporting portion and extends toward the first circuit board, a supporting portion which is attached at a predetermined distance away from the second circuit board on the side surface of the second connector and surrounds the outer circumference of the second connector; and a wall portion which is attached to the supporting portion and extends toward the first circuit board, wherein a length of the wall portion, measured from a first end of the wall portion on the second circuit board side to a second end on the first circuit board side is greater than the distance between the position of the first end and the surface of the first circuit board when the first and second connectors are fit to each other, wherein the second end of the wall portion comes into close contact with the one surface of the first circuit board by being pressed by the first circuit board, and wherein the wall portion is elastically deformed in a direction of separation from the interface between the first and second connectors (4, 5).