A drive transmission device having motor, a first pulley configured to be driven to rotate by the motor, a second pulley configured to be connected to a device, and a belt unit configured to be wound around the first pulley and the second pulley. The belt unit includes a metal layer and a dielectric layer configured to be provided between the first pulley and the metal layer and between the second pulley and the metal layer. The drive transmission device also includes a voltage supply unit configured to supply voltage to cause attraction between the first and second pulleys and the belt and a controller configured to control the voltage of the voltage supply unit based on information indicating load of the device.