A piston structure of a pumping-type cosmetic container. The piston structure includes two pistons which come into close contact with an inner wall of a container body and are overlapped. During a pumping operation, a first piston firstly ascends to a certain section and then lifts up a second piston located on the lower part thereof such that the first piston and the second piston ascend together; thus, it is possible to reduce the volume taken up by the pistons when the contents are initially filled, while the thickness for a normal operation of the pistons is still maintained, so that relatively more contents for the same volume can be filled in the same container.