PROBLEM TO BE SOLVED: To provide a method and a device capable of properly determining the timing at which charging stage should be transited in multistage control of a charging current.SOLUTION: In a method for multistage control of a charging current, at least one stage is a constant current stage. In the constant current stage, dormant sections Int1, Int2 are provided, in terms of a predetermined cycle Tx, in which charging is suspended for only a predetermined suspending time intx. The dormant section includes a measuring section which is stated after a predetermined delay time &Dgr;d from the suspension start time. Voltage drop &Dgr;Vb(n) at both ends of the measuring section is measured and when &Dgr;Vb(n) exceeds a predetermined threshold, transition control to next stage is performed.
