Dielectric measurement using the time domain reflectometry made on poly(vinylpyrrolidone) (PVP)-water mixtures exhibits a relaxation process due to reorientation of water molecules. If the concentration of PVP is lower than 57 wt %, the mixture freezes between 0 and -19 degrees C. Relaxation strength drops at that point and disappears altogether at -57 degrees C. On the other hand, mixtures with concentration higher than 57 wt % have no freezing point. These results indicate the existence of three kinds of water in the mixture. The first one, disappearing at the freezing point, is the same as pure water. The second one, which disappears at -57 degrees C, forms a distorted cluster consisting of five water molecules and a repeat unit of PVP. The third one, which has no freezing point, forms a nonordered structure among polymer chains.