Battery charging apparatus

A battery charging apparatus includes a switching power source supplying a current to a battery pack (2), an input voltage detecting unit (100) detecting an input voltage of the switching power source, a charging current control unit (60) that detects a charging current of the battery (2) and controlling the charging current in accordance with a charging current set value, and a microcomputer (50) detecting whether the current supplied to the battery (2) to be charged is less than a predetermined value on the basis of a detection signal of the input voltage detecting unit (100) and controls the charging current set value in accordance with the input voltage. When it is discriminated that the input voltage is less than a predetermined value on the basis of the detection signal, the microcomputer (50) sets the charging current set value to be a value less than the predetermined value.