To increase the sound insulating properties without adverse effect on the basic performance excellent in transparency, whether resistance and adhesion by placing a specific interlayer between 2 or more glass sheets and restricting the dissipation factor within a certain frequencies.

A polyvinyl alcohol with an average polymerization degree of 500-5,000 is dissolved in warm water and held at a prescribed temperature, for example, at 0-95°C. Then, an acid catalyst and an aldehyde are added to proceed the acetalization with stirring. Then, the temperature is raised to complete the reaction, the reaction mixture is neutralized, washed with water and dried to give a powder of polyvinyl alcohol. In order to reduce the polyvinyl acetate component lower than 30mol.%, the polyvinyl alcohol to be used has a saponification degree of ≥70mol%. The aldehyde to be used for preparing an interlayer containing at least one of resin layer has 3-10 carbon atoms, a prescribed amount of a plasticizer is formulated to form an interlayer. The interlayer is placed between 2 or more glass plates to give a laminated glass sheet with a dissipation factor of ≥0.1 in the frequency range of 1,000-3,000Hz at 10-40°C.