WORKING MACHINE

A working machine according to an embodiment of the present invention includes an air cooling system, wherein a cooling airflow flowing between a prime mover (E1) and a ceiling portion (183) of a prime mover room (ER) is mixed with an exhaust gas (203) from the prime mover inside the prime mover room and wherein the mixture is discharged to the outside of the prime mover room through a discharge portion (228).