<；P>；PROBLEM TO BE SOLVED: To provide a system capable of collecting inexpensively positional information of a lightweight small animal having about 10-30g and existing in about 1 kg of bleeding case. <；P>；SOLUTION: A wide dynamic range of load cell is not required to be used, by preparing a support column 2 for supporting a weight separately from a load cell for finding a change of the center of gravity, and the system is thereby provided at low cost. The inexpensive system is introduced even in a development institute evaluation-incapable until now, by providing the inexpensive system, and an organization is set up to serve for allowing research by a large number of researchers. The present invention contributes to enhancement in scientific level in research and development of medicines, functional foods or the like. <；P>；COPYRIGHT: (C)2009,JPO&INPIT
