PROBLEM TO BE SOLVED: To provide a nutrition diagnosis aid for dogs and cats capable of assisting so that the nutritional status of the dogs and cats can accurately be diagnosed without variations by a simple method of a BCS.SOLUTION: An aid for use in diagnosis of the nutritional status of dogs and cats by a body condition score (BCS) is provided, and has five places of simulated chest side parts 11-15 being made to correspond to respective step of the five-step method by the BCS. Each of the simulated chest side parts 11-15 comprises a base unit 16 including two or more protrusions 17 simulating ribs on the surface, a simulated muscle fat layer part 18, and a simulated skin fur part 19. In the five places of the simulated chest side parts 11-15, the thickness and elasticity of the simulated muscle fat layer part 18 and the simulated skin fur part 19 are set respectively so that the hardness obtained when vertically pressing a rubber and plastic hardness meter 30 from the outside of the simulated muscle fat layer part 18 toward the base unit 16 may change in a stepwise manner according to the BCS in the part of the protrusions 17 simulating the ribs.
