The utility model relates to a sliding fastener. The body of the fastener is fixedly provided with a cover body repetitively conducting sliding displacement on the body. One side of the body is provided with a holding hole. One side of the holding hole is outward extended with a gap groove. One side of the cover body is also provided with a corresponding gap groove. Corresponding magnetic elements are arranged between the body and the cover body. When the cover body is wrenched to be in the state of misplaced pushed moving on the body, the mutually attracted magnetic elements can be separated and the annular neck of the preset male fastener is extended in the holding hole. Then the cover body is pushed back. The cover body can automatically adsorb and return to the original position using the characteristic of magnetism mutual attraction. Therefore, the annular neck of the preset male fastener is fastened and held to form a stable fastening and holding state. Therefore, the effect of simple structure, convenient use and no looseness and separation is achieved.