<p>An adhesive sheet for application to flexible vinyl chloride resin articles such as blood bags made of a flexible vinyl chloride resin and having a center-line surface roughness Ra of 1.0 µm or higher. It comprises a film base and a heat-sensitive adhesive layer formed on the back side thereof, wherein the heat-sensitive adhesive layer is made of a resin comprising a crystalline polyester resin as the main component. The adhesive sheet has excellent adhesion when applied to articles made of a flexible vinyl chloride resin. Even after an autoclave treatment or low-temperature storage, the adhesive sheet does not decrease in adhesion strength and suffers neither lifting nor peeling. It further has excellent blocking resistance.</p>