Disclosed is a switching device of a tractor, comprising a housing (1), wherein the housing (1) is provided with a telescopic line roller (2) coiled with a dog rope, a locking block (3) and a switch (4) the locking block (3) is controlled by the switch (4) to be switched between a working position and an idle position when the locking block is in the working position, the line roller (2) is stopped rotating the locking block (3) is provided with a locking end (31) which is clamped to the line roller (2) and a fixing end (32) which is connected to the housing (1) the locking block (3) rotates by taking the fixing end (32) as the centre of a circle, so that the locking end (31) is switched between the working position and the idle position the fixing end (32) is provided with a torsional spring (33), and the torsional spring (33) applies to the locking block (3) a torsional force enabling the locking end (31) to rotate to the idle position a buckle (21) matching with the locking block is arranged on the sidewall of the line roller (2) which is around a line roller rotating centre array and when the locking block (3) is rotated to the working position, the locking end (31) is clamped to the buckle (21). According to the switching device of the tractor, a press-type switch which is of a simple structure is adopted to integrate opening and locking operations of the tractor, thereby the switching device is flexible and easy to use and a plurality of protection and fracture prevention measures are carried out to achieve firmness and durability.Linvention concerne un dispositif de marche/arrêt pour dispositif de traction, comprenant un boîtier (1), le boîtier (1) comprenant un enrouleur télescopique (2) sur lequel est enroulée une laisse de chien, un bloc de verrouillage (3) et un bouton (4) le bloc de verrouillage (3) est commandé par le bouton (4) pour être commuté entre une position activée et une position désactivée lorsque le bloc de verrouillage est en position activé
