Two types of microwave variable phase shifters of a coplanar waveguide with float electrodes on both sides and a float electrode on one side using ferroelectric liquid crystal are discussed. The measured phase shift is proportional to the frequency of the microwave according to the theory, and the measured phase in the both-sided-electrode device is larger than that in the one-sided-electrode device. The measured phase shift increases with increasing applied voltage in both devices. The response time of the both-sided-electrode device is less than 1 ms above 120 V, and a very high speed variable phase shifter is realized.