A storage battery apparatus comprising: a plurality of storage battery modules (MDL), each of which includes a battery module (BT) including a plurality of battery cells, a first wireless communication module configured to transmit and receive a radio wave based on a BLE standard, and a cell monitoring unit (C2) configured to measure a voltage of the battery cell and a temperature of at least one portion of the battery module (BT) and control operation of the first wireless communication module ; and a battery management unit (BMU1, BMU2) which includes a plurality of second wireless communication modules (BLE1 to BLE4) configured to transmit and receive a radio wave based on the BLE standard, and an arithmetic processing apparatus (C1) configured to control operation of the second wireless communication modules (BLE1 to BLE4), wherein the arithmetic processing apparatus (C1) is configured to divide the plurality of storage battery modules (MDL) into a plurality of groups (GR1, GR2) each including at least one of the storage battery modules (MDL), and is configured to establish communication between the battery management unit (BMU1, BMU2) and the storage battery modules (MDL) in unit of the group (GR1, GR2) according to an external command, the plurality of groups (GR1, GR2) includes a first group (GR1) and a second group (GR2), and the arithmetic processing apparatus (C1) is configured to establish connections with the storage battery modules (MDL) by receiving an advertisement packet as an observer after transmitting an advertisement packet which requests a connection as a broadcaster, and is configured to start operation of connections with the storage battery modules (MDL) included in the second group (GR2) after communication with all the storage battery modules (MDL) included in the first group (GR1) is established. a plurality of storage battery modules (MDL), each of which includes a battery module (BT) including a plurality of battery cells, a first wireless communication module configured to transmit and receive a radio wave based on a BLE standard, and a cell monitoring unit (C2) configured to measure a voltage of the battery cell and a temperature of at least one portion of the battery module (BT) and control operation of the first wireless communication module ; and a battery management unit (BMU1, BMU2) which includes a plurality of second wireless communication modules (BLE1 to BLE4) configured to transmit and receive a radio wave based on the BLE standard, and an arithmetic processing apparatus (C1) configured to control operation of the second wireless communication modules (BLE1 to BLE4), wherein the arithmetic processing apparatus (C1) is configured to divide the plurality of storage battery modules (MDL) into a plurality of groups (GR1, GR2) each including at least one of the storage battery modules (MDL), and is configured to establish communication between the battery management unit (BMU1, BMU2) and the storage battery modules (MDL) in unit of the group (GR1, GR2) according to an external command, the plurality of groups (GR1, GR2) includes a first group (GR1) and a second group (GR2), and the arithmetic processing apparatus (C1) is configured to establish connections with the storage battery modules (MDL) by receiving an advertisement packet as an observer after transmitting an advertisement packet which requests a connection as a broadcaster, and is configured to start operation of connections with the storage battery modules (MDL) included in the second group (GR2) after communication with all the storage battery modules (MDL) included in the first group (GR1) is established. <EOS>