A medium conveyance apparatus including a first unit on one side of a conveyance path of a sheet-shaped medium, a second unit on the other side of the conveyance path and facing the first unit, a guide unit that is provided at the second unit and that contacts the medium between the first and second unit to move the second unit in a direction of separating from the conveyance path, an imaging unit provided at one of the first and second unit, a reference plate whose image can be captured by the imaging unit and that is provided at the other of the first and second unit, and a detecting unit for detecting the medium in the conveyance path, the detecting unit being provided in the conveyance path at an upstream position of a reading position where the imaging unit reads the medium.