Abstract: A breeding cage which does not require separate members for connecting frames of a trunk portion of the cage together, which is easy to handle, and which has an appointed cylindrical shape that hardly changes when the frames are connected together. The frames are formed by fixedly mounting crossing members to one side of a plurality of parallel horizontal members made of metallic wires. The frames are connected at respective end portions thereof along a line extending axially of the cylindrical trunk portion. A plurality of connecting wires intersect the horizontal members at substantially right angles and are fixedly mounted to the horizontal members at one of the end portions where the frames are connected to each other. A plurality of wire portions extend from the horizontal members at the other of the end portions. The wire portions overlap the respective connecting wires. Specifically, the wire portions extend between the connecting wires and overlie opposite sides of the connecting wires.