A device for the manufacture of a continuous foam layer starting from a foam forming mixture and comprising an endless conveyor (4) which rotates in one direction and provides a surface arranged for producing the foam layer thereon. The conveyor (4) comprises slats (35) which form said surface and which are mounted on links (37, 38) of a chain structure (36). In order to avoid gaps between the different slats (35), especially as a result of different thermal expansion coefficients of the slats (35) and the chain structure (36), the slats are slidably mounted in the rotation direction of the conveyor (4) onto said chain structure (36) and have such a width that, when moving in said surface, they push each other forward, relative to said chain structure (36), in the rotation direction of the conveyor (4).