A power converter is required to be compact, lightweight and low loss, and the various approaches have thus been carried out so far. For a forward converters (FC) used for step-down of medium-capacity, many papers that aims at its miniaturization by coupling the isolation transformers and the output reactors have been reported. Each method of the integrated magnetic components (IMC) shows that the position of the windings and the gaps are different and the total volume becomes smaller than that before coupling. However, it is not clear which method should be adopted to obtain the desired performance and what kind of characteristics it can judge from. Therefore, we classified the FC's IMC from the way of the coupling and investigate the operation of the FC depending on the winding of the IMC in this paper. As results from simulation and experimental analysis, the winding position suitable for the FC, the way of reducing the volume of the magnetic component and suppressing the ripple of the input/output current became clear.