A sheet supporting apparatus includes a cassette body supporting a sheet, a regulation device disposed on the cassette body in a moving direction and regulating a position of an edge of the sheet, and a plurality of engaged portions disposed on the cassette body. The regulation device includes a body portion, an engaging portion moving between an engagement position at which the engaging portion engages with one of the engaged portions and a separation position at which the engaging portion is separated from the engaged portions, an operation member pivotably supported on the body portion and operated between a first posture at which the operation member positions the engaging portion at the engagement position and a second posture at which the operation member positions the engaging portion at the separation position, and a retention portion retaining the operation member at the first posture.