An image-forming device includes a main casing having a paper tray; a belt accommodated in the main casing; a plurality of developing units juxtaposed along the belt; a mounting member configured to detachably support the plurality of developing units, the mounting member being configured to be pulled outward from the main casing in a pulling direction; and a guide member configured to drawably guide the mounting member from the main casing, the guide member being configured to move between a first position and a second position, the second position being farther from the belt than the first position. When the guide member is at the second position, a first distance between the paper tray and a downstream end portion of the guide member in the pulling direction is shorter than a second distance between the paper tray and an upstream end portion of the guide member in the pulling direction.