A continuous casting mould comprises a mould tube (12), a mould jacket (24) surrounding the mould tube (12), a cooling system (26) within the mould jacket (24) for cooling the mould tube (12), an oscillating lever (40) supporting the mould tube (12). The oscillating lever (40) is capable of oscillating about a pivoting axis (45) substantially perpendicular to a casting plane containing the casting axis (20) for transmitting mechanical oscillations to the mould tube (12). An oscillating mould cover (30) associated with the top end of the mould jacket (24). The mould tube (12) is supported with its upper end by the oscillating mould cover (30), and is itself pivotably supported by the oscillating lever (40) outside of the mould jacket (24). A sealing element, e.g. an annular lip seal (90), provides sealing between the oscillating mould cover (30) and the top end of the mould jacket (24).