PURPOSE: To allow a window frame to be removed from a sash frame as occasion demands.

CONSTITUTION: In a double-shaft swinging window provided with a double-shaft slip-off preventing device, at least one place among four bearing parts provided at a sash frame 40 is formed into a shaft removing body 120 formed of a supporting shaft bearing base body 100 fixed to the sash frame 40, and a removable body 110 removable from the supporting shaft bearing base body 100. In the case of being fixed to the supporting shaft bearing base body 100, the removable body 110 has a receiving part 121 for enclosing a window frame supporting shaft 71 protruding onto the window frame 40 side, and in the case of removing the removable body 110 from the supporting shaft bearing base body 100, the shaft removing body 120 becomes incapable of enclosing the window frame supporting shaft 71 protruding onto the sash frame 40 side.