PURPOSE: To provide a bent product polishing and grinding device having the capability of polishing the external surface of a metallic elbow tube efficiently and to high quality.

CONSTITUTION: The main section of this device is constituted of a main head 2 having a pair of buff wheels 4A and 4B for forming a polishing zone 10 at an intermediate position in between, and a workpiece holder 3 on the upper side of the forward end of an arm type bracket 6 for insertion in the hollow section of an elbow tube 1 for the retention thereof. Also, the wheels 4A and 4B have a rotation mechanism moving in an arrow A direction as well as a revolution mechanism moving in an arrow B direction. Furthermore, the holder section 3 has a mechanism advancing and retreating in an arrow C direction for having the jig 5 near and part from the wheels 4A and 4B, and a rotating mechanism for causing the jig 5 to rotate and reciprocate along the curved form of the elbow tube 1. The elbow tube 1 mounted on the jig 5 is positioned in the polishing zone 10 at an intermediate position between the wheels 4a and 4b, and made to give a reciprocating motion under rotation for polishing the whole external surface thereof.