A protective circuit board and a battery pack using the protective circuit board broadens a mount region of a device and improves operability and processibility thereof. The battery pack comprises: a bare cell including a cap plate and an electrode terminal; and a protective circuit board positioned at the outside of the bare cell and formed of a flexible printed circuit board where a protection module, a positive temperature coefficient thermistor, and first and second power terminals are mounted. Accordingly, a space for mounting a number of protection devices and a space for forming a high current pattern are secured, and the work of mounting the protection devices and forming the high current pattern are easily performed. Furthermore, since any special structure for compensating a difference in the height of a protection device and an electrode terminal is not needed, the operability and processibility increase.