The present disclosure relates to a juicer with improved juicing performance, and particularly, includes a motor housing, a drive part including a motor which is provided inside the motor housing, a connecting part which is formed with an inserting hole which is formed at one side of the motor housing and through which a rotary shaft penetrates, the rotary shaft transferring a driving force of the motor, a roller part which is detachably coupled to extend forward from the connecting part, and is provided therein to be rotatably driven by the driving force transferred from the drive part, and a hollow fastening guide which is formed in the inserting hole to improve a sealing force for the rotary shaft, thereby providing an advantage of greatly improving a juicing force of the juicer.