Substrates were subjected to oblique ion irradiation while polyamide films were deposited by a vacuum deposition polymerization method from terephthaloyl chloride and p-phenylenediamine. Uniaxial orientation in the plane of the films was determined by IR measurements with polarized light parallel and perpendicular to the direction of ion irradiation. Evident dichroism of C=O bands was observed in the spectra of the firm deposited with oblique ion irradiation. The dichroism indicates that the polyamide film has orientation in the plane; polymer chains are aligned parallel to the substrate and to the incident plane of ion irradiation. Orientation depends on the irradiation angle of ions to the substrate, and this dependence changes according to whether acceleration voltage is applied to the substrate or not. When acceleration voltage is applied, the orientation shows maximum value at the glancing angle of the ions. In the case of floating substrates, the orientation becomes maximal at the angle of 40 degrees. Angle dependence of the orientation indicates that oblique ion irradiation gives in-plane anisotropy to the polyamide. Orientation of the films was also affected by both the value of the acceleration voltage and me ion current.