The speed of chloride penetration caused by cracking at the concrete surface is determined by the crack width. In this study, the impact of the cracks that can occur on the concrete surface (occurring from the contraction during concrete curing) on the chloride penetration speed was revealed through modeling. The accuracy of the established model was also verified through laboratory testing. The definition of the minimum crack width that affects the chloride penetration speed was established, based on testing and consideration of literature. The comparison of crack widths (20, 85, 125μm) based on the chloride profile and model prediction showed that there is virtually no chloride penetration at 20 μm, while the chloride penetration speed increased sharply at crack widths of 85 μm and 125 μm.