A separating device for separating first and second bones or cartilage parts comprises a first structure with a first elongated member and a stationary engaging member at one end of the first elongated member; a second structure with a second elongated member and a separation member at one end of the second elongated member; a moving device for moving the second structure relative to the stationary engaging member from a contracted position to a closed position. An angular position of the first and the second structures are adjusted, so the subsequent movement of the separation member towards the closing position intersects a separation area between the first and second bones or cartilage parts causing an immediate separation between the first and second bones or cartilage parts.