A pouch type lithium secondary battery having a positive temperature coefficient element disposed to rapidly operate depending on an increase in the temperature of the battery, thereby improving the thermal stability of the battery. The pouch type lithium secondary battery includes: an electrode assembly including a first electrode plate to which a first electrode tab is attached, a second electrode plate to which a second electrode tab is attached, and a separator interposed between the first and second electrode plates; a pouch material having a space in which the electrode assembly is received; a protection circuit module having a junction pad, for controlling charging and discharging of the electrode assembly; and a positive temperature coefficient element which has one end attached to the junction pad, and the other end electrically connected to one of the first and second electrode tabs, so as to interrupt electric current when a temperature of the battery rises.