To provide a rotary brush 1 for an electric floor-polisher for cleaning floor faces or the like, of which the problem of rotary vibration is solved to improve the operability, and of which the bristle members 16 can be replaced.

A bristle planting seat 2 in a disc shape is divided into two upper and lower components composed of a base disk 3 and a bristle planting board 4 respectively, and the lower member of the bristle planting board 4 has a recessed section 4a formed on the upper face, into which the upper member of the base disc 3 is fitted to lower the center of gravity. This rotary brush 1 for electric floor-polisher is characterized in that a fine gap is formed between the joint surfaces of the base disc 3 and the bristle planting board 4 to enable repeated touches and separations between both members, and/or to interpose a cushion material 16 between the joint surfaces.