A sheet supporting apparatus includes first and second units. The first unit includes a first housing, first and second lock portions, a first shaft configured to be supported rotatably with respect to the first housing and to turnably support the first lock portion, and a second shaft configured to be supported rotatably with respect to the first housing and to turnably support the second lock portion. The second unit includes a second housing and first and second engagement portions provided in the second housing and configured to engage respectively with the first and second lock portions. The first and second shafts are disposed such that extension lines of rotational axes of the first and second shafts cross with each other in a plan view.