用接触式量仪测量曲面，通常得到的测量数据是实际曲面的等距曲面。等距曲面的一般理论是ＣＡＧＤ中有待探索的热门课题，螺旋面却是一个简单的特例：螺旋面的等距曲面也是螺旋面。本文作者运用螺旋线的偏置曲线的理论证明这个命题。以此为依据可使螺旋面测量数据的处理简便易行。 Surface measurement with a contact meter, usually the measured data is the actual surface of the equidistant surface. The general theory of equidistant surfaces is a hot topic to be explored in CAGD. However, the helical surface is a simple special case: the equidistant surfaces of helical surfaces are also helical surfaces. The author of this paper uses the theory of helix bias curves to prove this proposition. Based on this, spiral surface measurement data can be processed easily.