The electromagnetic field simulator includes a discrete model setting section which sets a space grid width and a time step in a simulation of the electromagnetic field, a coefficient setting section which sets coefficients of equations for the simulation at various positions in a simulation space based on electromagnetic physical properties, a wave source setting section which sets a position and amplitude of a wave source of the electromagnetic wave as a boundary condition with respect to a spatial distribution of the electromagnetic field, and an amplitude calculation section which calculates amplitude of an electromagnetic field component given to the position of the wave source in the simulation space based on the space grid width and the time step and the electromagnetic physical properties at the position of the wave source to reproduce the electromagnetic wave having the set position and amplitude of the wave source in simulation results.