The invention relates to the technical field of switches and in particular relates to a tear switch comprising a reset part, an action part and a switch part. In the operation of an adhesive tape machine, when a foreign object penetrates through an adhesive tape, a pull rope at one end of the tear switch is triggered to laterally pull an action rod in order to drive the action rod to move axially.A protrusion portion on the action rod inside the tear switch is pressed against a micro switch in the tear switch so as to make a contact point operate. A red reset handle, moved behind the tear switch by structural change, laterally slides a locking block pressed against a protruded sensor block into the pulled-out end of the action rod through an internal connecting shaft. A positioning rod isprovided to block the sliding locking block so as to maintain the tear switch in an action state. A handle locking block is switched back to be pressed against the protruded sensor block again to reset the tear switch. The sealing of elastic folding rubber seal and the change of the reset handle position effectively prevent the intrusion of water and dust, improve the working efficiency of the adhesive tape machine, reduce the replacement cost of production spare parts, and achieve strong practicality.