To finish grinding work of the inner peripheral surface of a member with through holes in a high quality by honing sticks.

A mandrel 30 and a mandrel supporting shaft 31 are provided on the same axis. While an engaging part 72 wherein a fitting hole 71 is drilled to fit the mandrel supporting shaft 31 is formed on the lower end side of the mandrel 30, leaf plates 75 installing a pair of honing sticks 77 are provided in a free advancing and retreating manner in the radial direction on the outer peripheral surface. In each plate spring 75, an inclined block 79 having an inclined surface 78 is provided. While the tip side of the mandrel 30 is inserted into the hole of a member with through holes, a conical inclined surface 81 at the tip of the mandrel supporting shaft 31 is abutted against the inclined surface 78 of each inclined block 79, the honing sticks 77 are rotated by rotating the mandrel 30 while controlling the projecting amount of the honing sticks 77, and furthermore, the mandrel 30 is moved in the axial direction of the hole so as to work the inner peripheral surface of the hole. Since this work is carried out on the same axis of the mandrel 30, a high quality can be obtained.