A battery control device controlling an operation of a battery connected to a power system includes detection means that detects battery-related information showing a state of the battery, or a state of an interconnection point of the power system and the battery, first communication means that transmits a detection result of the detection means to an external device, and executes reception processing to receive operation control information to control the operation of the battery from the external device at a predetermined time interval, and control means that executes battery operation control processing to control the operation of the battery based on a state of the power system and based on the operation control information received by the first communication means, at a time interval shorter than the predetermined time interval.