To provide a storage battery device having a detection function of stable and highly accurate charge/discharge current and an output power to temperature variations, and having little power loss.

In the storage battery device composed of a storage battery 1, storage battery output terminals 9, 10 connected to an external electronic apparatus, a charge/discharge control circuit 52, a switch circuit for charging 39 and a switch circuit for discharging 38, the switch circuits are constituted of a sense FET 27 and a power FET 28, and a sense FET 29 and a power FET 30 connected in parallel, sense resistances 19, 20 for current detection are connected to respective drain sides of the sense FET 27, 29 in series, measuring the voltages of both ends of the resistances and both ends of the sense FET 27, 29, and calculating and detecting the charge/discharge current by the arithmetic circuits 25, 26.

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