Disclosed is a portable charging apparatus having a built-in charging battery, which can easily charge the charging battery of a cellular phone even in a place where home AC power or car power cannot be used and can be used for various kinds of portable equipment by means of using one charger. The present invention can charge a charging battery of a cellular phone using home AC power or car power. Furthermore, the charger of the present invention can easily charge the charging batteries of various digital mobile devices such as cellular phones using an internal charging battery included therein even in a place where home AC power or car power cannot be used.