PROBLEM TO BE SOLVED: To provide a service vehicle prime mover structure capable of efficiently cooling a tail pipe, ensuring the high draw-in capability of a radiator fan and the high exhaust capability of a dust discharge fan, suppressing the overheat of an engine, and ensuring the less frequency of maintenance and inspection work.SOLUTION: The object is attained by disposing a driver seat and an engine E below the driver seat, disposing an oxidation catalyst device 11 oxidizing unburned fuel contained in exhaust gas discharged from the engine E in an internal region of a vehicle body above the engine E along a front-rear direction, connecting a tail pipe 15 to an outlet 12 of the oxidation catalyst device 11, and causing the tail pipe 15 to face a space formed between a milling device 3 and a grain tank 5 in a back view.
