This invention concerns an immobilisation mask, wherein the immobilisation mask (2) comprises a sheet of thermoplastic material for receiving the body part to be immobilized, and is provided with connection means (21) for connecting the immobilisation mask (2) with the carrier (3). The connection means comprise at least one profile (1) that is provided on a first side with first connection means (5, 15, 21) for connecting the profile to the carrier (3), wherein the first connection means (5, 15) are provided, in the connected state, to engage corresponding connection means along the outer edge (4) of the carrier (3), and on a second side opposite the first side, second connection means (22) for connecting the profile with the immobilisation mask. The first connection means (5, 15, 21) are provided, in the connected state, to engage corresponding connection means (13) along the outer edge (4) of the carrier (3).