To provide a separation device, for an ambulatory animal, by which the ambulatory animal can be separated in a simple operation without a need of a troublesome operation and to provide a weighing apparatus provided with the separation device.

In a separation device for an ambulatory animal, a door body 20 and a door support part 19 are installed at the entrance part of a guidance passage GR in which the ambulatory animal is passed and moved. The separation device is constituted in such a way that a guidance plate 3, in a longitudinal posture, which guides the ambulatory animal on the upstream side in the movement direction of the ambulatory animal from the door support part 19 is attached to the door support part 19 and that the guidance plate 3 can form a passage whose width becomes wider on the upstream side in the movement direction of the ambulatory animal. In addition, a weighing apparatus is constituted in such a way that a weighing platform 2 which weighs the passing and moving ambulatory animal is fixed and coupled to a fence 4 which regulates, in the transverse-width direction, the passage of the ambulatory animal which is passed and moved on the weighing platform 2 and that the separation device for the ambulatory animal is fixed and connected to the entrance part IM of the weighing platform 2.