PURPOSE: To brush teeth by motion by which a flocked bundle is twisted, in addition to bass brushing and rolling brushing.

CONSTITUTION: In this motor-driven toothbrush, a brush body 2 executes motion of bass brushing and rolling brushing by driving of a driving shaft 4. In this case, a floating shaft 5 being freely rotatable against the brush body 2, and also, being freely slidable in the longitudinal direction against the brush body 2 is inserted through the brush body 2. A fixed shaft 6 inserted through in the driving shaft 4 and the floating shaft 5 are coupled to each other. Rotary boards 7, 8 having a flocked bundle 3 are installed by plural pieces in the brush body 2 so as to be freely rotatable. The rotary boards 7, 8 and the floating shaft 5 are interlocked by a gear mechanism of a screw gear, a helical gear, etc. In such a way, not only at the time of bass brushing but also at the time of rolling brushing, the rotary boards 7, 8 rotate and the flocked bundle 3 carries out twisted motion.