A coplanar waveguide type microwave phase shifter using ferroelectric liquid crystal is constructed and its fundamental characteristics are measured. An analysis procedure of the effective permittivity of the phase shifter is explained. The decrease of the width of the center conductor in the phase shifter leads the increase of the dielectric permittivity change, consequently increasing the phase shift. The distance between the center conductor and ground plane needs the same as the width of the center conductor. Furthermore, it is confirmed that the arrangement of the dielectric substrate instead of the liquid crystal layer is useful technique.