To provide a minute test piece polishing device which hardly bends or damages a minute test piece, and makes the quality of the manufactured minute test piece uniform with high working efficiency.

In this minute test piece polishing device 1, the surface of the minute test piece 3 with round cross section is polished by using a string-like member 13. The device is composed of: a string-like member delivery and recovery means 10; a polishing material attaching means 20; a gripping and rotating means 30; and a pressing and scanning means 40. The polishing material is attached to the string-like member delivered by the string-like member delivery and recovery means 10 by the polishing material attaching means 20. Then, the string-like member 13 with the polishing agent is pressed and scanned by the pressing and scanning means 40 relative to the minute test piece 3 gripped and rotated by the gripping and rotating means 30, thereby polishing the minute test piece 3.