Abstract: The invention relates to a device for changing a compression ratio of an internal combustion engine. The device comprises a connecting-rod head (1) with an eccentric bearing (2), an eccentric (3) which is mounted rotatably in the eccentric bearing (2) and which comprises a piston pin bearing (3), a piston pin (5) which is mounted rotatably in the piston pin bearing such that, by means of rotation of the eccentric the position of the piston pin relative to the connecting rod head (1) can be adjusted from a top dead centre to a bottom dead centre and vice versa, and a locking device (8) for locking the eccentric at the top dead centre.