DTS MG created ‘Disk Needle Roller’ system – a circular disk of a drum is formed by integrating a metal disk having a plurality of needles. When pricking the skin with the disk needles, the needles do not give severe damage to the skin and can be prevented from being broken, thus being effectively used for a lengthy period of time. The circular disks and the retainers of the drum have respective simple structures and are closely assembled with each other such that the disks and the retainers can be prevented from being undesirably moved relative to each other, thus realizing stable operation of the skin stimulator and preventing foreign substances from being jammed in the drum.