Disclosed is a walk-behind self-propelled machine that includes a drive motor； a handle comprising two grips operative to be held by a left hand and a right hand of a user； a speed adjusting element configured to move relative to the handle to adjust a rotational speed of the drive motor, and configured to be operated by the user when the user holds one of the two grips with a single hand, the speed adjusting element being disposed between the two grips； and an electromechanical converting device configured to convert a positional change of the speed adjusting element relative to the handle into an electrical signal for adjusting the rotational speed of the drive motor. The speed adjusting element is movable relative to the handle between a first position and a second position. The rotational speed of the drive motor when the speed adjusting element is in the first position is greater than the rotational speed of the drive motor when the speed adjusting element is in the second position. The disclosed walk-behind self-propelled machine is convenient and easy to operate.
