The invention concerns image-recording apparatus, which records an image onto a sheet-film. The image-recording apparatus includes a mainframe; a main/sub-scanning unit that includes a main-scanning unit to expose a light-beam onto a sheet-film by scanning the light-beam in a main-scanning direction and a sub-scanning unit to convey the sheet-film in a sub-scanning direction; and a supporting member to mount and support the main/sub-scanning unit onto the mainframe at a supporting position. The height of the supporting position is substantially the same as that of a center of gravity of the main/sub-scanning unit. The sub-scanning unit is detachably integrated with the main-scanning unit to form the main/sub-scanning unit.