(Subject)To provide an electro-magnetic field analysis technique of an electric rotating machine that filters through a specific higher-harmonic at a specific portion.(Construction)The first electro-magnetic field analysis procedure of analyzing the electro-magnetic field in an analysis space based on the first boundary condition in terms of an electro-magnetic variable assigned to the first specific portion in the analysis space; a development procedure 2 of developing the electro-magnetic variable at the second specific portion in the analytic space, obtained in the first electro-magnetic field analysis procedure, into each higher-harmonic component; the second boundary condition setting procedure of assigning an electro-magnetic variable in terms of at least one of the higher-harmonic components, developed from the above electro-magnetic variable, to the second specific portion as the second boundary condition; and a procedure 3 of analyzing the electro-magnetic field of the analysis space based on the first and second boundary conditions are executed on a computer.