A numerical prediction was performed to clarify the air motion in the swirl chamber of a diesel engine. On the modeling of the flow, the k-ε model was adopted. Flow simulation has been carried out three kinds of swirl chamber shapes with different sorts of connecting passages including a sub-passage. The shifts of the swirl generation and spatial distribution of turbulent intensities during a compression stroke were predicted. It was found that the swirl chamber shape has a significant effect on the tangential velocity and turbulence intensity. The latter decreases in the initial stage of the compression stroke, and after that, it increases with an increase of the inlet momentum and the shear force based on the inlet flow.