The utility model relates to a machine parts, in particular to bolt. Including the bolt body, the bolt body including the nut and with nut integrated into one piece's screw rod, still including the swivel nut with screw rod screw -thread fit, the bottom of screw rod be equipped with a fixed column, be equipped with the anti -disengaging mechanism who prevents the bolt and drop between this fixed column and the swivel nut. Anti -disengaging mechanism including fixed orifices, spacing hole and spacing post, the fixed orifices be equipped with swivel nut bottom and fixed column and can insert andlocate in the fixed orifices, spacing hole be equipped with the lateral wall of fixed orifices and switch on with the fixed orifices, spacing post locate the side of fixed column, the fixed column onbe equipped with the spring mechanism that can make spacing stake pocket go into spacing hole or the spacing hole of roll -off. The utility model provides an anticreep bolt, no matter how two parts shake, and the bolt can not drop, can solve the problem that the background art provided.