The purpose of this study was to measure the hardness and Young's modulus from data obtained from a nanoindenter that could perform precise nanoindents as well as high-resolution surface imaging. The value of penetration hardness was determined from the load-penetration depth curve obtained from this instrument, and the effective Young's modulus was calculated from the slope of the unloading curve. In addition, these methods were applied to measure the mechanical properties of a silicon nitride film deposited to the stainless steel by the are ion-plating method, The penetration hardness of the film was measured to be 38.7 GPa. However, when converted into micro-Vickers hardness, the value became 2070. The effective Young's modulus was 191 GPa.