The invention provides a switch structure, a gear shifting fork, a neutral and reverse gear control structure and a speed changer. The switch structure comprises a plug seat assembly, a contact assembly and a first spring. The plug seat assembly comprises a seat body, a sliding seat, an interface and an output contact head, wherein a middle part of one side of the seat body is provided with an opening, the other side of the seat body is open, the sliding seat is mounted in the opening of the seat body, and the interface is mounted in such a way that the interface is abutted against a part, positioned at the open side, of the seat body; one end of the output contact head is mounted in the opening while the other end does not extend beyond the interface; the contact assembly is mounted in the plug seat assembly and comprises a contact point rack, a first contact sheet, a second contact sheet and a spacer bush, wherein one end of the contact point rack is in contact with the output contact head, the first contact sheet can contact with the other end of the contact point rack to form a first closed loop circuit, the second contact sheet can contact with the other end of the contact point rack to form a second closed loop circuit, the spacer sleeve is mounted between the first contact sheet and the second contact sheet, and the first spring is abutted against the interface and is mounted in the sliding seat. Via use of the neutral and reverse gear control structure provided in the invention, a switch can be used for switching between a neutral gear and a reverse gear.