In order to evaluate an effect of cancer treatment by hyperthermia, and induction heating by alternating current quantitatively, electromagnetic field – heat conduction coupled analysis in a parallel environment has been studying. The models which are analyzed in this study have over 100 million degrees of freedom (DOFs), due to the fact that they have very small structures compared to the space and take into account the skin effect. The efficient parallel computing method for large-scale finite element analysis (FEA) that has been studying in this study is the iterative substructuring method in the form known as the domain decomposition method (DDM) based on the iterative method. It is expected to obtain scalable parallel efficiency on distributed memory parallel computers with the implementation of a Hierarchical Domain Decomposition Method (HDDM). The previous system which consisted of separate solvers and a coupler took a long time. In this study, to reduce the computational time, a new system that integrates all the necessary functions built using the ADVENTURE_Magnetic (AdvMag) library which generalizes the FEA and HDDM functions for AdvMag is proposed. As a result, the total computational time of the one-way coupled analysis has been reduced by 25%.