Sheet feeding apparatus and image forming apparatus

A sheet feeding apparatus comprising:

• a stacking portion on which a sheet is stacked;
• a rotary feeding member configured to feed the sheet stacked on the stacking portion, toward an image forming portion in a sheet feeding direction;
• a first separation portion including a separation surface disposed so as to contact the sheet fed by the rotary feeding member;
• and
• a detachable unit detachably attached to the first separation portion, the detachable unit including a second separation portion that contacts a sheet fed by the rotary feeding member so as to separate the sheet, together with the separation surface, one by one,
• wherein a direction that intersects both the sheet feeding direction and a rotation-axis direction of the rotary feeding member, and that extends from the separation surface toward the rotary feeding member is defined as a projection direction,
• the second separation portion is positioned downstream of the separation surface in the projection direction in a state where the detachable unit is attached to the first separation portion, and
• another portion of the detachable unit other than the second separation portion is positioned upstream of the separation surface in the projection direction in a state where the detachable unit is attached to the first separation portion.