A charge pump device is disclosed. The charge pump device includes a driving stage, for generating a driving signal corresponding to a driving capability; a charge pump circuit, for generating an output voltage according to the driving signal; a comparing circuit, comprising a first comparator for comparing the output voltage and a first reference voltage to generate a first comparing result; an overload detection circuit, for generating a detection result according to at least one of the first comparing result and the output voltage; and a driving capability control circuit, coupled between the overload detection circuit and the driving stage for controlling the driving capability corresponding to the driving signal according to the detection result.