To easily rescue a bathing person who has fallen down in a bathroom by freely opening and closing a wing sash of a door part comprising a collapsible door, the wing sash and a fitting frame from the outside of the bathroom.

A door part is formed by a collapsible door bent inward a bathroom to be opened and closed, a wing sash 3 installed on the side of the collapsible door, and a fitting frame to which the collapsible door and the wing sash 3 are fitted. Subsequently, the right side of the wing sash 3 is journalled to the fitting frame by a rotatable shaft 34, and the left side of the wing sash 3 is locked to the fitting frame by a fixing pin 35 which can be slid in the vertical direction and can be unlocked from the outside of the bathroom. Subsequently, the fixing pin 35 is connected to a lever 35 built in the upper part of a vertical frame 36, and when the lever 36 is lowered, the groove of the fixing pin 35 is dislocated from a rail so as to unlock from the outside of the bathroom. When a bathing person fell down in front of the collapsible door, the collapsible door is hard to be opened, and the wing sash 3 is freely opened and closed from the outside of the bathroom. Therefore, the wing sash 3 is opened toward the outside of the bathroom to enter the bathroom, so that the fallen bathing person can be easily rescued.