A battery pack having no need to fill a gap between a bare cell and a protective circuit module includes a safety vent adapted to properly function even after molding has been completed and a PTC thermistor having characteristics which do not degrade during manufacturing processes. A bare cell, which has a protective circuit module and a PTC thermistor mounted thereon, is enclosed by an integral case. An exposed area of the case is covered with a resin. A lead is positioned on a safety vent formed on the bare cell to prevent the safety vent from being fractured by a resin of a high temperature and pressure during a resin filling process. The resin does not reach the protective circuit module and the PTC thermistor so that its heat is not transmitted to them.