Because of change in woman's social status, the number of working women is growing and the demand of the breast pump is increasing as well. Commercial products of the, breast pump are applying only negative pressure for sucking and many users feel a pain for a long term use. Whereas a baby is using peristaltic motion as the result of tongue and jaw action in addition to suction. In this research, therefore the breast pump with a baby-like motion is developed. In order to realize baby-like peristaltic motion, a cam mechanism is applied. Also, for producing negative pressure, a crank mechanism is utilized. As the result, it turns out that the breast pump developed is realized the same peristaltic motion and suction pattern as a baby.