The present invention relates to an image-forming device having mechanism for separating developing rollers from photosensitive drums. The laser printer includes a contact/separation mechanism that linearly moves developing cartridges between contact positions where the developing cartridges contact corresponding photosensitive drums and separating positions where the developing cartridges separate from the photosensitive drums. The contact/separation mechanism includes a pair of contact/separation members and a synchronous moving mechanism. The contact/separation members are disposed one on either side of the developing cartridges. The synchronous moving mechanism is for linearly moving the contact/separation members with synchronization with each other.