The invention provides a work machine. A prime mover part (8) positioned in a machine body front part is provided with a bonnet (20) for covering the outer periphery and an air cleaner (28) positioned inside its bonnet 20. An operation part (14) positioned in a rear part of the prime mover part (8) is provided with a brake pedal (17) projecting upward from an operation part step (13). A rear side air intake port (73) to the air cleaner (28) is formed in a place positioned above the operation part step (13) and in a place in close vicinity to the brake pedal (17), in a rear side surface opposed to the operation part (14) of the bonnet (20). According to the invention, the air cleaner can well supply combustion air regardless of a different in a work state.
