To provide a medium transport apparatus that puts a curved transport path including a movable member for changing the size of a space of the curved transport path into a proper state depending on usages regardless of the rigidity of a medium.

The medium transport apparatus 1 includes a movable flap 16 that forms part of the curved transport path and guides a copy to the downstream in the curved transport path which conveys the copy while curving it. The movable flap 16 is disposed so as to be swingable at the outside of the curved transport path, and changes the size of a space of part of the curved transport path by swinging. The movable flap 16 has a swing center 16a in an upstream direction of a guide surface 16b that guides the copy.