An image forming apparatus includes a pair of regulating members, for regulating movement of a recording material conveyed from a secondary transfer portion toward an intermediary transfer belt side, configured to be contactable to the recording material at both end portions with respect to a width direction perpendicular to a conveyance direction of the recording material; a moving mechanism capable of moving a position of the pair of regulating members with respect to the width direction; a recording material size detecting portion for obtaining width information of the recording material with respect to the width direction perpendicular to the conveyance direction; and a width control portion for controlling the moving mechanism so that the pair of regulating members to a position correspondingly to the width information obtained by the recording material size detecting portion.