Abstract: [PROBLEM] To provide a interlocking device and a packaging bag therewith wherein the interlocking device has sufficient heat stability against retort sterilization treatment and deformational change after said treatment small enough not to be impaired its reopenability. [SOLUTION MEANS] A interlocking device having a pair of male and female profiles wherein: said male and female profiles have non-heat-sealing part to bag body and heat-sealing part to bag body; where said non-heat-sealing part consists of polypropylene type resin composition (A) having main melting peak temperature observed by differential scanning calorimetry less than 150 degree C. and the melt flow rate at 230 degree C. from 0.5 g/10 min to 20 g/10 min; and said heat-sealing part consists of polypropylene type resin composition (B) having main melting peak temperature observed by DSC, not less than 140 degree C. and the melt flow rate at 230 degree C. from 0.