An electricity management apparatus includes: a communication unit for receiving electricity information through a smart grid electricity information network, or transmitting electricity management information on an electronic device connected to a network through an internal network; a reference value setting unit for setting a total area, and setting a maximum allowable electricity reference value and an inspection electricity reference value corresponding to the set total area; and a controller for performing controlling to determine a management mode for each electronic device connected to the internal network, in consideration of an electricity proportional value comparing a current accumulated used electricity value comparing a current time to a certain time, when a current inspection used electricity value exceeds the set inspection electricity reference value, and to transmit the electricity management information corresponding to the determined management mode.