PURPOSE: To harmonize the appearance of a rotary window with a curtain wall by installing a vertical shaft rotary window which is smaller than an opening, in a part of a curtain wall to which glass panes are attached so as to shield the vertical frames of a window or vertical members.

CONSTITUTION: A window having a width which is smaller than that of an opening defined between transoms 1, 1 and vertical members 20, 2 is installed near to the vertical member 20. In this arrangement, a longitudinal middle rib 5 partitioning the opening is attached to the middle parts of the vertical members 20, 2. Further, a glass pane 15 on a sash 14 is sealed by a seal material 4 which is used to be filled in vertical frames 18, 19, similar to glass panes 3 on the curtain wall. In this arrangement, the upper and lower edges of the glass pane are absorbed by horizontal frames while it is supported by the vertical frames 18, 19 and the horizontal frames. Further, find-out pieces of the horizontal frames on the outside of a room are laid in a plane the same as a plane where find-out pieces of the transoms 1 and the vertical members are laid. Further, the glass pane 15 is laid in a plane the same as a plane where the glass panes 3 on the curtain wall is laid. With this arrangement in which the vertical shaft rotary window 13 is installed, concavities and convexities at the opening are eliminated, thereby it is possible to ensure the continuity between the transoms 131 or the vertical members 2 and the glass panes 3, 15.