Provided is a cover material for packaging contains for retort sterilization which comes to exhibit excellent sealing strength through low-temperature, short-time heat sealing. The cover material for packaging containers for retort sterilization is constituted of a multilayered laminate obtained by superposing a base layer, an interlayer, and a sealing layer in this order, and is characterized in that the base layer is constituted of a laminated film obtained by laminating a polyethylene terephthalate film or polybutylene terephthalate film to an aluminum foil and the aluminum foil of the base layer has been laminated to the interlayer with a polyurethane-based adhesive or a polyester-based adhesive, and that the aluminum foil has a thickness of 7-40 μm, the polyethylene terephthalate film or the polybutylene terephthalate film has a thickness of 6-18 μm, the interlayer has a thickness of 10-100 μm, and the sealing layer has a thickness of 3-20 μm.