Abstract: A small animal rearing apparatus (1) has a frame (2) of a rectangular shape, a rearing unit having a plurality of rearing sections (4) formed in vertical arrangement and provided respectively with floor boards (15) sloping down toward the front. Spray nozzles (18) are disposed respectively above the high rear ends of the floor boards (15) to spray washing water from the high rear ends of the floor boards (15) toward the low front ends of the same along the upper surfaces of the same, respectively. The high rear end of the floor board (15) of each rearing division (4) underlying the spray nozzle (18) does not have any raised part. The spray nozzle (18) can be disposed with its axis extended substantially in parallel to the upper surface of the floor board (15). A downward rear rim (15a) is formed by bending downward a rear edge portion of each floor board (15).

Abstract: An air supply/exhaust device to be joined to a box-shaped rearing cage included in an experimental animal rearing apparatus to supply or exhaust air into or from the rearing cage. The air supply/exhaust device comprises an air supply pipe having a front end section provided with air supply/exhaust holes, and a stop ring mounted on a section of the air supply pipe behind the front end section provided with the air supply/exhaust holes. An elastic plug is mounted on a section of the air supply pipe extending behind the stop ring so as to be in contact with a back surface of the stop ring. The elastic plug has the shape of a truncated cone tapered toward an extremity of the air supply/exhaust pipe, and a spring holder is provided on the air supply pipe, and an elastic pressing member is mounted on a section of the air supply pipe between the elastic plug and the spring holder to press the elastic plug continuously toward the stop ring.