PROBLEM TO BE SOLVED: To provide a technology to enable accurate measurement of individual calorie consumption of each water source heat pump unit in an individual air conditioning system using the water source heat pump unit.SOLUTION: The individual calorie consumption measuring method measures the individual calorie consumption of a water source heat pump unit 3 based on a heat source water flow Qw supplied to a heat exchange coil 62 and a heat source water temperature difference ΔTHw before and after heat exchange with a heat medium. An inlet side temperature sensor and an outlet side temperature sensor are installed at an inlet side branch pipe 21 and an outlet branch pipe 22 respectively. Using an inlet side temperature waveform and outlet side temperature waveform obtained from each temperature sensor during no load period when the compressor 50 of the water source heat pump unit 3 is under suspension, synthetic instrument difference specific processing is performed to determine the synthetic instrument difference ΔIE between the two temperature sensors by obtaining at least one of the maximum value and minimum value thereof. This processing is implemented prior to processing for a heat source water temperature difference.