A heat exchanger equipped with a cold reserving part, the heat exchanger comprising: a first header tank and a second header tank which are provided in parallel to be spaced apart from each other at a predetermined distance and are partitioned in an air flow direction by a barrier rib to form a first compartment to a third compartment; tubes of three columns which have both ends fixed to the first compartment to the third compartment of the first header tank and the second header tank, respectively, wherein a heat exchange medium moves in the tube of the first column and the third column and a cold reserving material is stored in the tube of the second column, characterized in that the heat exchanger further comprises: an inlet and outlet forming member which includes a manifold mounted at one side of the first header tank, whereas the manifold includes a lower manifold and an upper manifold, an inlet pipe connected to the manifold to introduce the heat exchange medium therein, and an outlet pipe connected to the manifold to discharge the heat exchange medium therefrom; a cold reserving material charging part which is integrally formed with the lower manifold to communicate with the second compartment communicating with the tube of the second column, wherein the cold reserving material charging part is provided with a screw thread on an inner peripheral surface thereof; and a stopper which includes a head part and a fixed part protruding at one portion of the head part to correspond to the screw thread of the cold reserving material charging part, such that the stopper is coupled to the screw thread of the cold reserving material charging part to close the cold reserving material charging part. a first header tank and a second header tank which are provided in parallel to be spaced apart from each other at a predetermined distance and are partitioned in an air flow direction by a barrier rib to form a first compartment to a third compartment; tubes of three columns which have both ends fixed to the first compartment to the third compartment of the first header tank and the second header tank, respectively, wherein a heat exchange medium moves in the tube of the first column and the third column and a cold reserving material is stored in the tube of the second column, an inlet and outlet forming member which includes a manifold mounted at one side of the first header tank, whereas the manifold includes a lower manifold and an upper manifold, an inlet pipe connected to the manifold to introduce the heat exchange medium therein, and an outlet pipe connected to the manifold to discharge the heat exchange medium therefrom; a cold reserving material charging part which is integrally formed with the lower manifold to communicate with the second compartment communicating with the tube of the second column, wherein the cold reserving material charging part is provided with a screw thread on an inner peripheral surface thereof; and a stopper which includes a head part and a fixed part protruding at one portion of the head part to correspond to the screw thread of the cold reserving material charging part, such that the stopper is coupled to the screw thread of the cold reserving material charging part to close the cold reserving material charging part.