An apparatus is provided. The apparatus includes a memory, a second type spectrum measurer, and a processor. The memory stores an individualized blood sugar estimation model. The second type spectrum measurer measures second type spectrum data for a skin of a user. The processor calculates blood sugar of the user based on the measured second type spectrum data and the individualized blood sugar model. The blood sugar model is generated based on blood sugar profile data of the user calculated based on a first type spectrum-blood sugar profile relationship model and training second type spectrum data for the skin of the user.