Manufacturing method for hollow rack bar and hollow rack bar manufacturing apparatus

A hollow rack bar manufacturing apparatus, the hollow rack bar made of a hollow shaft material and including a toothed section which has a rack on an outer surface and a shaft section which is formed thinner than the toothed section, the apparatus comprising:

• a die having a working section configured to define an outside diameter of the hollow shaft material;
• a plug having working sections configured to define inside diameters of the hollow shaft material;
• a driving unit configured to move the plug in an axial direction of the hollow shaft material;
• and
• a drawing unit configured to draw the hollow shaft material through between the die and the plug,
• wherein the plug has a first working section and a second working section having a larger diameter than that of the first working section, as the working sections, and
• wherein when a toothed section forming region of the hollow shaft material configured to form the toothed section passes through the die, the driving unit disposes the first working section of the plug inside the working section of the die configured to define the outside diameter of the hollow shaft material, and when a shaft section forming region of the hollow shaft material configured to form the shaft section passes through the die, the driving unit disposes the second working section of the plug inside the working section of the die.