A variable magnification copying apparatus capable of not only one-to-one magnification copying but also reduction copying, and particularly a variable magnification copying apparatus of the slit exposure scanning type which is capable of two or more types of reduction copying and which uses two movable mirrors and an in-mirror lens on the object side, characterized in that the optical axis of the in-mirror lens is set non-parallel to an original carriage to make the apparatus compact and during magnification change, the in-mirror lens and the second movable mirror are initially displaced by predetermined distances in predetermined directions, whereby the object point position and image point position of an image forming principal light ray on the original supporting surface and photosensitive surface are made fixed irrespective of the copying magnification.