CHARGING DEVICE

A charging device includes a charge controller (14) which receives input of voltages at two ends of a shunt resistor (13) in synchronization with turning on of a switching device (12), sets an on-time during which the switching device (12) is turned on based on the inputted voltages at the two ends of the shunt resistor (13), and controls a charge current of a secondary battery (11). A resistance value of the shunt resistor (13) is set equal to or above a value obtained by dividing a least resolution of an A/D conversion voltage when the charge controller (14) converts an inputted analog voltage into a digital voltage by a minimum detectable value of the charge current of the secondary battery (11).