In an assembly in which a space between two elements is filled with a filler containing resin, a configuration that can limit both the size of the assembly and the cost of the fillers is provided.
Assembly 10 of stacked elements has: first element 2 having first surface 21; resin layer 61 that is arranged on first surface 21 and that contains a plurality of fillers F; and second element 4 that is arranged on resin layer 61 and that has second surface 41 that is in contact with resin layer 61. In a section that is perpendicular to second surface 41, the average flattening ratio of fillers F2 that are in contact with second surface 41 is larger than the average flattening ratio of fillers F1, F3 that are not in contact with second surface 41. Here, the flattening ratio is a ratio of the maximum length of the filler in a direction parallel to second surface 41 to the maximum thickness of the filler in a direction perpendicular to second surface 41.