PURPOSE: To provide a common rate charge allocating device for residents in a building by which a total value of demand amounts to the whole tennants is made to coincide with a demand amount of a supplier even if total quantity used by the respective tennants and quantity used in meter inspection of the supplier are different from each other.

CONSTITUTION: Respective tennants in a single building 1 use respectively electricity E1-E3, city water W1-W3, gas G1-G3 and so on. Electricity E1 quantity being used is measured by a meter ME1. The others are measured similarly by respective meters. Meter values are taken in a building monitoring device 2. When a rate demand is received from a supplier, a rate charging system 4 divides a rate by a total value of the respective meters according to quantity used in a demand rate, and multiplies this divided value by measured values of the respective meters, and determines burden amounts of the respective tennants.