A switch structure which includes an alloy piece, a contact control device, and a push device is disclosed. The contact control device includes an elastic part and connects to an end part so that the end part may reciprocally move with respect to the contact control device in a horizontal direction. The end part normally contacts with the upper side of the stopper placed in the switch body and is used to push the push device towards the end part when the alloy piece is overheated and strain is generated due to the current flowing through the alloy piece. The end part then elastically contracts and escapes from the stopper to fall down so that another end of the contact control device projects upwards and does not press the elastic contact plate. Therefore, the elastic contact plate may escape from the two contact points to cut off the power source rapidly by the elastic force to achieve the purpose of safety.