A clutch transmission device for a self-propelled mower comprises a housing assembly (11, 12), a shaft rod (20), a worm wheel assembly (30), a worm (40), a sliding sleeve (62), a rocker-arm (63), a return spring (64) and a clutch stay wire. Compared with the prior art, the driving motor for the cutter of the mower drives the transmission assembly, and the transmission assembly drives the worm (40) and the worm wheel assembly (30), and the worm (40) drives the shaft rod (20) by the cooperation of the balls (32) and the holes, such that the clutch transmission device engages the transmission assembly and the wheel of the mower. The clutch transmission device has small size, novel and reliable structure, low friction loss and clutch noise, and has no transmission-lock components, such as keys or pins. The parts of the device are easy to produce. The device is easy to operate and has complete disengagement and has no slipping.
