A shell and tube type water-cooled EGR cooler capable of increasing an efficiency of heat exchange between exhaust gas and cooling water, wherein a plurality of spiral projection lines are formed on the inner peripheral surfaces of tubes passing through plates and spiral wire material is closely fitted into the tubes, a bonnet located on an exhaust gas inlet side is formed in a bell mouth shape of which the bore increases gradually toward the flow direction of the exhaust gas; a flat box-shaped shell and tube type water-cooled EGR cooler, wherein a bonnet (6A) on an exhaust gas inlet side is formed in a bell mouth shape, and a truncated-chevron guide plate (21) is disposed in the bonnet and a round bar (22) is disposed at the intermediate position of each guide plate.
