EGR COOLER

The invention provides an EGR cooler comprising tubes (3) and a shell (1) enclosing the tubes (3); cooling water (9) is supplied into and discharged from said shell (1); exhaust gas (10) is guided from a diesel engine into the tubes (3) for thermal exchange of the exhaust gas (10) with the cooling water (9). A bypass flow path for guiding the cooling water (9) is constituted within the shell (1) so as to prevent stagnation of the cooling water (9) in the shell (1).