A sheet sorting apparatus comprising a first tray, a second tray, a conveyance unit, a tray detection unit, a stacking amount detection unit, and a control unit configured to control the conveyance unit to not convey the sheet to the second tray, in a case where the stacking amount detection unit detects that the amount of sheets reaches the predetermined amount, wherein the control unit is configured to permit the conveyance unit to convey the sheet to the second tray, in a case where the tray detection unit detects that the first tray is detached from the apparatus main body in a state where the stacking amount detection unit detects that the amount of sheets reaches the predetermined amount and conveyance of the sheet to the second tray by the conveyance unit is stopped.