A door opening and closing apparatus opens and closes a slide door by cooperating with a guide roller unit fixed to the slide door of a vehicle. The guide roller unit includes a guide member and a belt-side bracket connected to the guide member. The door opening and closing apparatus includes a support member made of resin, plural pulleys supported at the support member, and a transmission belt engaged at the plural pulleys. The support member is fixed to a body of the vehicle and includes a rail portion at which the guide member is mounted. The belt-side bracket is fixed to the transmission belt. An electric drive source moves the transmission belt for opening and closing the slide door in a state where the guide member is guided along the rail portion. The support member includes an engagement portion configured to hold the belt-side bracket.