PURPOSE: To make quick rescue possible in such an emergency when a person falls in a bathroom by a method wherein an open space is provided below a horizontal rail provided to outer peripheral frames of a bathroom door, and an auxiliary door that is detachable in case of emergency is installed to such open space.

CONSTITUTION: A horizontal rail 4 is provided to a specified location in an outer peripheral frame 3 of a bathroom door 1, and an open space 9 is formed, being encircled with the horizontal rail 4, the outer peripheral frames 3 on both sides and a lower rail 5 for an auxiliary door or a lower frame 6 of the bathroom door. The auxiliary door 2 for emergency rescue in a shape that can be fitted to each of the rails and the frames 3-6 forming the open space 9 is provided. Engaging pieces- projecting/retreating mechanisms 10, 10 constructed of springs 10a, engaging projecting pieces 10b and pulling handles 10c, 10c are provided to an outer frame part 10b of the auxiliary door 2. The engaging projecting pieces 10b are normally engaged with the horizontal rail 4 by energizing force of the springs 10a, and thereby the auxiliary door 2 is fixed to the open space 9. In such an emergency when a person falls in the bathroom, the pulling handles 10c are pulled down, resisting agains the energizing force of the springs l0a, to retreat the engaging projecting pieces 10b, and the auxiliary door 2 is removed.