A lawn mower (1) includes a housing (3), a motor (4) which is connected with the housing and is provided with a motor shaft (6), a mowing blade (8) connected with the motor shaft and having at least one cutting edge (10), a power providing device which provides the motor with power when the lawn mower works so as to rotate the blade at a cutting speed. The lawn mower also includes a speed control device (14) which can achieve constant speed control, and the speed control device under the constant speed control state maintains the cutting speed at one predetermined constant speed at least.
