PURPOSE: To display the electric power consumption rate or the like in each dwelling and in an administrative room on a real basis, regarding an apartment house equipped with a digital private branch exchange (PBX).

CONSTITUTION: This system is provided with every unit measurement means 1a and 1b to measure a power consumption rate or the like of each unit 1 and send digital data, a calculation data transmission means 1e to calculate a rate from the digital data and send data related to a consumption and calculation to a control room 3 via PBX 2, and a calculation means 3a laid in the control room 3 to add the calculation data of each unit 1 sent via the PBX 2 for every unit. Furthermore, the system is provided with a memory means 3b to save data received from the calculation means 3a, and a display means 3c to show data received from the means 3b for each unit 1. In addition, each unit 1 is provided with a memory means 1f to store data from the means 1e and a display means 1g to show the calculation data from the means 1e.