A storage battery unit (1) including a storage battery (2) and a monitoring device (3) that monitors a state of the storage battery using an output of the storage battery as an input, wherein, in order to prevent the monitoring device from consuming electric power in a state before use of the storage battery and prevent nonfunctioning of the monitoring device in use of the storage battery, a starting circuit (4) is provided between the storage battery and the monitoring device (3), the starting circuit including: a main switch that holds an OFF state in a state before a load is connected to the storage battery and interrupts supply of electric power from the storage battery (2) to the monitoring device; and a switch drive circuit that detects a reduction in terminal voltage of the storage battery that occurs when the load exceeding the set value is connected to the storage battery, and sets the main switch to an ON state.