Method for producing a mold casting device and cast bar

Mold 13 is provided with a recess 21 for receiving the melt 2. Recess 21, together are constituted by the inner wall surface 29 for varying the melt 2 to the coagulum in contact with the melt 2 and is open toward the drawing direction D1 of coagulum. A first contour line 23p curve by a second contour line 25p, has a cusp at the position of the start point 43 and 45. The distance from the first contour line 23p in the width direction D2 to the second contour line 25p are continuously increases as one proceeds from the upstream side to the downstream side of the pull-out direction D1. Through the first end point 33 or the second end point 35, about an axis perpendicular to the cross section of the mold 13, so that the cast bar 3 in the clockwise direction or counterclockwise direction may rotationally displaced, the inner wall surface of the concave portion 21 shape 29 is defined.