This paper presents a study on drawing condition dependences of optical absorption at 630 nm and nonbridging oxygen hole centers (NBOHCs) in optical fibers drawn from low‐OH‐content synthetic silica glass. The intensity of the 630‐nm absorption is proportional to the NBOHC concentration, and the value of the oscillator strength for the NBOHC is 4.2×10−4, which nearly equals the theoretical values. These results confirm that the 630‐nm absorption is due to the NBOHCs in low‐OH‐content silica glass. Furthermore, the 630‐nm absorption increases with increasing drawing tension. This drawing tension dependence is explained by applying kinetics of the stress‐induced crack growth in metal to the formation of the NBOHCs in the drawing process.