The present invention provides a duplex pouch and a heat-sealing mould for manufacturing the same. The duplex pouch has a pressure-openable non-sealing line of which a specific portion can be opened by a dynamic load that is generated when an external force is applied thereto, and includes a first chamber and a second chamber that are sealed by an external sealing line at their edges and a middleportion of the two chambers is heat-sealed by an inside sealing line to contain different types of liquid contents, respectively, a pressure-openable portion formed at the middle portion of the inside sealing line, a non-sealing unit formed in a rounded triangular or semicircular shape at the center of the pressure-openable portion by first and second branch sealing lines divided by the inside sealing line and then extended, a long non-sealing line provided in a middle of the first branch sealing line and communicating the first chamber and the non-sealing unit, and a short non-sealing line provided in the middle of the second branch sealing line and communicating the non-sealing unit and the second chamber. The heat-sealing mould forms the pouch by heat-sealing two sheets of films, and long and short notches may be formed in the first and second branch sealing pads that correspond to the first and second branch sealing lines, or long and short heat sinks may be formed between the first and second branch sealing lines.