Temporary connection and pyrotechnic separation device with a longitudinal axis (X) comprising a pyrotechnic expansion tube (14) mounted in a space (11) formed in a connection zone between a first (2) and second assembly (4) to be separated, the second assembly (4) being formed of a stack of plies (12.1, 12.2) bonded together, the two assemblies (2, 4) being connected to each other by two metal parts (10.1, 10.2), said metal parts being fixed onto the first assembly and bonded onto the outer plies (12.1) of the second assembly (4), the bonding area between said outer ply (12.1) and the adjacent inner ply (12.2) is less than the bonding area between two inner plies (12.2) forming a fuse ply, such that, when the pyrotechnic expansion tube (14) is used, the outer ply (12.1) separates from the adjacent inner ply.