A driving transmission device includes a motor, a first pulley, a second pulley, an endless belt which is wound on the first pulley and the second pulley, dielectric layers disposed between the endless belt and the first pulley and between the endless belt and the second pulley, and a power source unit. A length of a portion of the endless belt which is wound on the second pulley is longer than a length of a portion of the endless belt which is wound on the first pulley. An amount of current supplied from the second pulley to the endless belt in a region in which the endless belt is wound on the second pulley is smaller than an amount of current supplied from the first pulley to the endless belt in a region in which the endless belt is wound on the first pulley.