An intermediate transfer device includes an intermediate transfer member, intermediate transfer member support members, and two frame members each including first and second positioning members each having a positioning portion. At least one of the frame members satisfies a condition L1:L2=2.85:x 0≦x≦1, where L1 is the length of a line segment connecting an intersection point to the positioning portion of one of the positioning members on a side opposite to a side toward which a line of action of a force applied by a second-transfer unit is inclined and L2 is the length of a line segment connecting the intersection point to the positioning portion of the other of the positioning members on the side toward which the line of action is inclined, the intersection point being an intersection of the line of action and a line segment connecting the positioning portions.