In this study, we present a full waveform inversion (FWI) method using controlled-source electromagnetic (CSEM) method to explore marine resources. We employed FDTD simulation using fictitious wave domain method to enlarge time step. As a result, calculation time by FDTD method for low-frequency wave propagation becomes faster with eight hundreds times than one by standard FDTD method. The resolution of our CSEM inversion method is discussed, considering orientation of the dipole of a transmitter and receivers. As a result, the inversion results highly depend on orientation of the dipole. We consider that it is efficient to employ different oriented dipoles of transmitter and receivers for accurate inversion. From results, we conclude it is possible to simulate realistic field data.