The infrared method is the most popular to measure the moisture content in the coated layer on the paper sheets or polymer films. But this method is not suitable for measuring only a little moisture content, for example less than 1%, with high accuracy because of the influence of the disturbance such as heat source. It is also affected by the color of the sample in principle. In order to solve these problems, a new moisture analyzer using a microwave resonator has been developed. This is based on the difference of the dielectric loss between the water and the paper sheets or polymer films. This report describes the measurement principle, some data and a few applications of the new moisture analyzer.