Abstract: Economic efficiency in power control including transmission and reception of electric power to and from an external power market is improved. An EMS serving as a power control device that is able to transmit and receive electric power to and from a power market and controls operations of one or more power instruments includes: a host control unit serving as a transmitted/received electric power determining unit configured to determine an amount of transmitted/received electric power which is an amount of electric power transmitted to and received from the power market based on a power-market unit price in the power market and information related to an operating situation of the one or more power instruments; and an intra-grid control unit serving as an operation instruction determining unit configured to determine an operation instruction for the one or more power instruments based on the determined amount of transmitted/received electric power.