A transfer device includes a plurality of transfer members and a switch section. The switch section, in a first state, causes the transfer members to be pressed against a plurality of image bearing members. The switch section, in a second state, causes a transfer member opposed to a first image bearing member to be pressed against the first image bearing member, and causes a transfer member opposed to a second image bearing member to be separated from the second image bearing member. In the first state, toner images of different colors are transferred from the image bearing members to an intermediate transfer belt and superimposed together. In the second state, a single-color toner image is transferred from the first image bearing member to the intermediate transfer belt. The switch section changes a pressing force of the transfer member to the first image bearing member between the first and second states.