A medium transportation apparatus includes a transportation portion for transporting a medium; a first structure unit for forming a first transportation path to guide and transport the medium in a first direction from an upstream side in a medium transportation direction toward a downstream side in the medium transportation direction; and a second structure unit for forming an accommodation space to accommodate a part of the first structure unit. The first structure unit includes a first region disposed outside the accommodation space on the downstream side in the medium transportation direction and a second region disposed inside the accommodation space on the upstream side in the medium transportation direction.