An apparatus for sealing tray-shaped or pot-shaped receptacles, such as blister packs or pots for storing dairy products, includes a sealing head having a sealing contour support, a heatable sealing contour and support plate, preferably with at least one guide bolt immobilized thereon allowing for a linear displacement of the sealing head relative to the support plate. At least one spring element impinges the sealing head with a point biasing away from the support plate. A spring seat plate is disposed between the sealing head and the support plate and can be linearly displaced in the same direction as the sealing head. A rubber mount associated with the sealing head serves as a joint element and allows the sealing contour support to be tilted about the axes that are perpendicular to the guide bolts. An adjustable element is interposed between the spring seat plate and the sealing head.