<p>A step unit (1) comprises: a step member (3) which is provided on the vehicle body side so as to be adjacent to a slide door of the vehicle and has a flat plate section (4) on which an occupant's foot is placed; and a drive device (2) which is affixed to the step member (3) and drives the slide door to open and close the slide door. The step member (3) is molded using a resin material and has a accommodation portion (5) which is provided with a bottom (5a) formed below the upper surface (4a) of the flat plate section (4). The drive device (2) is affixed while at least a part thereof is accommodated within the accommodation portion (5).</p>
