A display device attached to a vehicle, comprising: a supporting member attached to a fixing member of the vehicle; and a display member detachably joined to the supporting member, wherein the display member includes a first case, a first circuit board stored in the first case, and a plurality of first connecting terminals electrically connected to the first circuit board, the supporting member includes a second case, a second circuit board stored in the second case, and a plurality of second connecting terminals electrically connected to the second circuit board, the first case has a first joint surface that is joined to the second case, the second case has a second joint surface that is joined to the first joint surface of the first case, the first connecting terminal has a distal end that is exposed on the first joint surface and comes into contact with a distal end of the second connecting terminal when the display member is attached to the supporting member, one of the first and second cases (20, 36) has a plurality of terminal mounting holes, characterized in that the terminal mounting hole has a large diameter portion, a small diameter portion, and a stepped surface formed at a boundary between the large diameter portion and the small diameter portion, one of the first and second connecting terminals (23, 38) is inserted into the terminal mounting hole, one of the cases (20, 36) includes a seal member that seals a gap between the one of the connecting terminals (23, 38) and the terminal mounting hole, and the seal member has an expanded portion radially extending outward, and an end protrusion, the expanded portion of the seal member is fit into the large diameter portion of the terminal mounting hole, the end protrusion of the seal member is exposed on one of the first joint surface and the second joint surface, comes into contact with the other joint surface (31, 40), and surrounds the distal ends of the first and second connecting terminals (23, 38) in contact to each other. a supporting member attached to a fixing member of the vehicle; and a display member detachably joined to the supporting member, wherein the display member includes a first case, a first circuit board stored in the first case, and a plurality of first connecting terminals electrically connected to the first circuit board, the supporting member includes a second case, a second circuit board stored in the second case, and a plurality of second connecting terminals electrically connected to the second circuit board, the first case has a first joint surface that is joined to the second case, the second case has a second joint surface that is joined to the first joint surface of the first case, the first connecting terminal has a distal end that is exposed on the first joint surface and comes into contact with a distal end of the second connecting terminal when the display member is attached to the supporting member, one of the first and second cases (20, 36) has a plurality of terminal mounting holes, characterized in that the terminal mounting hole has a large diameter portion, a small diameter portion, and a stepped surface formed at a boundary between the large diameter portion and the small diameter portion, one of the first and second connecting terminals (23, 38) is inserted into the terminal mounting hole, one of the cases (20, 36) includes a seal member that seals a gap between the one of the connecting terminals (23, 38) and the terminal mounting hole, and the seal member has an expanded portion radially extending outward, and an end protrusion, the expanded portion of the seal member is fit into the large diameter portion of the terminal mounting hole, the end protrusion of the seal member is exposed on one of the first joint surface and the second joint surface, comes into contact with the other joint surface (31, 40), and surrounds the distal ends of the first and second connecting terminals (23, 38) in contact to each other.