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.