To provide an inside diameter grinding device capable of machining a workpiece without generating a suddenly rising grinding load due to interference between a grinding tool and the workpiece, namely, adhesion against the axial force.

This inside diameter grinding device is provided with a holding means 16 for holding the workpiece having a lower hole, the grinding tool 12 arranged so that axis of the lower hole and axis of the grinding tool itself exist on the nearly same line, a rotating means 14 for rotating at least one of the workpiece and the grinding tool around the axis, and a driving means for moving at least one of the workpiece and the grinding means along the axis. This inside diameter grinding device is also provided with a control means for relaxing the force in the axial direction to be generated by interference between the grinding tool and the workpiece.