The copper electroplating is tried to apply on the fabrication of Large-Scale Integration (LSI) besides other methods because of its excellent via/trench filling ability, good adhesion and lower process temperature and cost. Then, in the electroplating process, estimating the growth rate of the electroplating in real-time is essential. It is able to estimate the growth rate from the current density on the LSI wafer surface because the growth rate of the electroplating is proportional to the current density. However, measuring the current density on the LSI wafer surface directly is impossible. In this paper, a new monitoring method to estimate the growth rate of the electroplating by using magnetic sensors is developed. We focused on the magnetic flux density induced by the current density in the electroplating device. The present method is measuring the magnetic flux density outside the electroplating device by using magnetic sensors, and estimating the current density on the LSI wafer surface by applying the inverse analysis method. In order to demonstrate the effectivity of the present method, two cases of numerical simulations, which take account the measurement error, are performed. The results show that this method could be applicable to practical problems.