PURPOSE: To measure the weight of an animal in a cage under the same condition by providing load receiving members which support the cage, cantilevers which carry strain gauges stuck to their cantilever arms and support the load receiving members by means of pins at their front ends, supporting members which support the cantilevers, and an arithmetic section.

CONSTITUTION: A cage 1 is supported by means of load receiving members 3 which support the top 2 edge sections of the cage 1 and each of the members 3 on both sides of the cage 1 is equipped with two pin receiving sections 8. Pins 7 at the front ends of cantilevers 6 fitted to supporting members 4 are inserted into the sections 8. In other words, the cage 1 is supported by the four pins 7. Stoppers 12 are installed to both ends of each member 3 so as to prevent the top plate 2 of the cage 1 from coming off from the members 3. Openings 10 are formed so that the cantilevers 6 can largely bend and strain gauges 9 are stuck to the cantilevers 6 at the positions of the openings 10. Both ends of the supporting members are respectively fixed to supporting channels 5 by means of joining members 11 and the load of the cage 1 is finally received by the channels 5. At the time of measuring the weight of the cage 1, a correction factor is found from the ratio of the weight of the cage measured by means of a balance to the value measured by means of the gauges 9 and the weight of the cage 1 is found by correcting the measured value of the gauges 9.