An image transfer device provided in an image forming apparatus in which, employing an endless belt as an intermediate transfer member, image transfer is performed at nip positions of a primary transfer portion and secondary transfer portion. Generation of warp in the transferred image resulting from transmission of fluctuations in load and torque of the endless belt generated at the nip position of one transfer portion nip to the nip position of the other transfer portion is prevented. The endless belt is turned between rollers and the endless belt is individually driven at the primary transfer portion and secondary transfer portion by drive sources to generate deflection between the primary transfer portion and the secondary transfer portion.