An image forming device includes a motor capable of positive rotation and reverse rotation, a photoconductor drum, a developing roller, a contact/separation cam and a switching cam. The contact/separation cam is configured to move the developing roller. The switching cam is configured to switch a position of a transmission member. An electromagnetic clutch is disposed between one of the contact/separation cam and the switching cam and the motor. The other cam is connected to the motor without the electromagnetic clutch. The contact/separation cam and the switching cam are driven by using the positive rotation and the reverse rotation of the motor and the electromagnetic clutch.