A walk-behind working machine includes a first clutch lever, a second clutch lever, and a throttle having a degree of opening controllable by each of the first clutch lever and the second clutch lever. The working machine also includes a pivoting member, a throttle wire connected to the pivoting member, and a first activating member provided to the first clutch lever for engagement with an engagement member provided to the pivoting member. When the first clutch lever is operated to place a first clutch in a connected state, the throttle is shifted by operation of the first clutch lever from a first opened position in which an idling engine speed is produced to a second opened position in which a working-machine-activating engine speed is produced.