To easily open/close a ventilation window and take in the outside air or cut off it as a door body is closed by housing an upwardly/downwardly moving structure of a glass sheet for opening/closing the ventilation opening formed in the door body, in the door body.

A ventilation window 1b is formed at the upper part of a door body 1 and an opening/closing drive structure 30 of a glass sheet 21 is housed in the inside of the door body. The drive structure is connected to an external electric source through a harness led from the side face of a hinge side of the door body 1 to the outside to drive a motor 41 in the normal or reverse direction through a switch 42 and move up and down the glass sheet 21 along the slide rail 50 by moving up and down a support frame 24 supporting the glass sheet 21. A rack and pinion structure can be used instead of a link structure 33. An insect net may be fixed to the ventilation window 1b or an insect net wound on a reel is provided to interlock with the glass sheet 21. In this way, the ventilation window 1b can be freely opened or closed as the door body 1 is closed, to form a ventilation opening.