PURPOSE: To form an indentation whose finish is satisfactory in a pin by beating a wire rod from the direction of the X axis or the Y axis against its axis, or beating it alternately from two directions of the X axis and the Y axis, indenting its part and deepening gradually the beating position.

CONSTITUTION: An operating body 9 for turning concentrically against an immobile disk 10 placed by surrounding the outside of a carrying line L of an object to be worked is placed. In the operating body 9, four slots 9a of the upper and the lower parts and the right and the left, etc., are formed at an interval of 90 degrees to each other on the same periphery being equal from the carrying line L. Dies 1, 1 for operating in the X axis direction and the slots 9a, and dies 1', 1' and the slots 9b are engaged to the axis center on the carrying line L. Subsequently, an arm 8a is held out of a base 8 to which the die 1 is attached, and a terminal 11 of its tip is fitted into the slot 9a. An arm 9c of the operating body 9 is brought to reciprocating motion by a cylinder 12. By shifting the engaged position of an engaging piece 13 of a tapered hole 9d of the arm 9c by a cylinder 14, the amplitude quantum of the operating body 9 is changed. In such a way, by beating alternately a wire rod from the X axis and the Y axis, an indentation whose finish surface is satisfactory can be formed.