A belt drive device that restricts, with respect to an endless belt laid under tension over a drive roller and a driven roller, meandering of the belt in a roller axis direction, comprising: a roller member that is arranged at each of both end portions of the driven roller in an axis direction thereof and restricts meandering of the belt in the roller axis direction, wherein the roller member has: a support shaft portion that is fastened to an apparatus main body; an elastic roller portion that is rotatably supported to the support shaft portion and with which, as a result of meandering of the belt, an end portion of the belt in a width direction thereof comes into contact; and a brake portion that is arranged between the support shaft portion and the elastic roller portion and brakes rotation of the elastic roller portion, the elastic roller portion is constituted by having: a side surface portion that is opposed to the end portion of the belt; and an outer peripheral portion that is opposed to an outer peripheral surface of the driven roller via a predetermined clearance, the clearance is configured to be smaller than a thickness of the belt, and when the end portion of the belt has entered the clearance against an elastic force of the elastic roller portion, a rotational load of the belt at the end portion is increased by using a braking force of the brake portion so as to restrict meandering of the belt in the roller axis direction. a roller member that is arranged at each of both end portions of the driven roller in an axis direction thereof and restricts meandering of the belt in the roller axis direction, wherein the roller member has: a support shaft portion that is fastened to an apparatus main body; an elastic roller portion that is rotatably supported to the support shaft portion and with which, as a result of meandering of the belt, an end portion of the belt in a width direction thereof comes into contact; and a brake portion that is arranged between the support shaft portion and the elastic roller portion and brakes rotation of the elastic roller portion, the elastic roller portion is constituted by having: a side surface portion that is opposed to the end portion of the belt; and an outer peripheral portion that is opposed to an outer peripheral surface of the driven roller via a predetermined clearance, the clearance is configured to be smaller than a thickness of the belt, and when the end portion of the belt has entered the clearance against an elastic force of the elastic roller portion, a rotational load of the belt at the end portion is increased by using a braking force of the brake portion so as to restrict meandering of the belt in the roller axis direction. a support shaft portion that is fastened to an apparatus main body; an elastic roller portion that is rotatably supported to the support shaft portion and with which, as a result of meandering of the belt, an end portion of the belt in a width direction thereof comes into contact; and a brake portion that is arranged between the support shaft portion and the elastic roller portion and brakes rotation of the elastic roller portion, the elastic roller portion is constituted by having: a side surface portion that is opposed to the end portion of the belt; and an outer peripheral portion that is opposed to an outer peripheral surface of the driven roller via a predetermined clearance, the clearance is configured to be smaller than a thickness of the belt, and when the end portion of the belt has entered the clearance against an elastic force of the elastic roller portion, a rotational load of the belt at the end portion is increased by using a braking force of the brake portion so as to restrict meandering of the belt in the roller axis direction. a side surface portion that is opposed to the end portion of the belt; and an outer peripheral portion that is opposed to an outer peripheral surface of the driven roller via a predetermined clearance, the clearance is configured to be smaller than a thickness of the belt, and when the end portion of the belt has entered the clearance against an elastic force of the elastic roller portion, a rotational load of the belt at the end portion is increased by using a braking force of the brake portion so as to restrict meandering of the belt in the roller axis direction.