It is an object of the invention to provide a plasticized polyvinyl acetal composition that is suitably used for an intermediate film of a laminated glass and other applications, specifically, the polyvinyl acetal composition being characterized in that in cases when a layer that is composed of the polyvinyl acetal composition and another resin layer such as a resin layer of a polycarbonate, a poly(meth)acrylic acid ester, or a styrene thermoplastic elastomer are laminated, the plasticizer does not migrate from the polyvinyl acetal layer. The present invention relates to a polyvinyl acetal composition including 100 parts by mass of a polyvinyl acetal and 0.5 to 100 parts by mass of an ester plasticizer or ether plasticizer that is amorphous or has a melting point of 30° C. or less, and has a hydroxyl value of 15 to 450 mgKOH/g.