A stacking device which is detachably attached to an apparatus body of an image forming apparatus having an abutting member that abuts on a recording material and on which a recording material is stacked includes: a first supporting unit that supports the recording material from a lower side of the recording material; and a second supporting unit that supports an end of the recording material in an attachment/detachment direction of the stacking device. The second supporting unit includes a corresponding region, and a position of the corresponding region agrees with a position of the abutting member abut with the recording material in a width direction which is orthogonal to the attachment/detachment direction. At least a height of the corresponding region in a direction orthogonal to the attachment/detachment direction and the width direction is lower than a height of the abutting member.