Provided is a rack apparatus for rearing laboratory animals with the ability to accommodate animal cages with different widths on a shelf plate, wherein the animal cages are not transversely displaced even by shaking etc. of the rack device, and a box-like exhaust part, in which air inside the animal cages flows to an exhaust box, is easy to clean. A plurality of animal cages (1) is stored at prescribed intervals in a storage space (16) on a shelf plate (15) supported by a frame structure (13). The rear of the storage space (16) is closed by a back plate (12b), the exhaust box (19) is installed at the top of the rear side, and a cage top cover (23) is installed at the top of the front side. A back stay (25) is demountably attached to the back plate (12b), a movement-restricting bar (27) is attached to the back stay (25), and spacers (29), which maintain intervals between the animal cages (1), are demountably attached to the back stay (25). The spacers (29) are selectively installed by mounting to/dismounting from the back stay (25) to maintain planned storage positions corresponding to the sizes of the cages (1) in the width direction.
