A latching mechanism applied to be mounted on a webbing of a seat belt system, and comprising: a tongue assembly; and a slider slidably mounted on the tongue assembly, being moveable upwardly and downwardly, and characterized in that the slider has a bridge located at a side of the tongue assembly; wherein the webbing passes through a bottom end of the bridge and is inserted through the slider and the tongue assembly; the webbing has a shoulder belt located at a side, which has the bridge thereon, of the latching mechanism; when the slider is located in an unlocked position of the tongue assembly, the latching mechanism is capable of freely moving along the webbing; a tension of the shoulder belt acts on the bridge for driving the slider to move from the unlocked position of the tongue assembly to a locked position of the tongue assembly, such that the webbing is clamped and locked by the slider and the tongue assembly; wherein the tongue assembly has an inserting portion and a guide portion connected to a top end of the inserting portion; the guide portion has a webbing receiving aperture formed through the guide portion; and a clamping base located above the webbing receiving aperture; and the slider has a webbing clamping bridge located below the bridge; the bridge and the webbing clamping bridge are located at the same side of the guide portion of the tongue assembly; the slider has an opening formed between the webbing clamping bridge and the bridge; the webbing passes through the bottom end of the bridge and is inserted through the opening of the slider and the webbing receiving aperture of the tongue assembly; the webbing is clamped and locked by the webbing clamping bridge and the clamping base; characterized in that the webbing clamping bridge of the slider has a webbing clamping surface; the webbing clamping surface is formed on the webbing clamping bridge, faces the tongue assembly, and has a clamping portion; the clamping portion is formed on the webbing clamping surface and is inserted into the webbing receiving aperture of the tongue assembly; the webbing clamping surface and the clamping portion exert respective clamping forces with the clamping base of the tongue assembly, such that the webbing is clamped between the webbing clamping surface and the clamping base and between the clamping portion and the clamping base, the respective clamping forces exerted in multiple directions. a tongue assembly; and a slider slidably mounted on the tongue assembly, being moveable upwardly and downwardly, and characterized in that the slider has a bridge located at a side of the tongue assembly; wherein the webbing passes through a bottom end of the bridge and is inserted through the slider and the tongue assembly; the webbing has a shoulder belt located at a side, which has the bridge thereon, of the latching mechanism; when the slider is located in an unlocked position of the tongue assembly, the latching mechanism is capable of freely moving along the webbing; a tension of the shoulder belt acts on the bridge for driving the slider to move from the unlocked position of the tongue assembly to a locked position of the tongue assembly, such that the webbing is clamped and locked by the slider and the tongue assembly; wherein the tongue assembly has an inserting portion and a guide portion connected to a top end of the inserting portion; the guide portion has a webbing receiving aperture formed through the guide portion; and a clamping base located above the webbing receiving aperture; and a webbing receiving aperture formed through the guide portion; and a clamping base located above the webbing receiving aperture; and the slider has a webbing clamping bridge located below the bridge; the bridge and the webbing clamping bridge are located at the same side of the guide portion of the tongue assembly; the slider has an opening formed between the webbing clamping bridge and the bridge; the webbing passes through the bottom end of the bridge and is inserted through the opening of the slider and the webbing receiving aperture of the tongue assembly; the webbing is clamped and locked by the webbing clamping bridge and the clamping base; characterized in that the webbing clamping bridge of the slider has a webbing clamping surface; the webbing clamping surface is formed on the webbing clamping bridge, faces the tongue assembly, and has a clamping portion; the clamping portion is formed on the webbing clamping surface and is inserted into the webbing receiving aperture of the tongue assembly; the webbing clamping surface and the clamping portion exert respective clamping forces with the clamping base of the tongue assembly, such that the webbing is clamped between the webbing clamping surface and the clamping base and between the clamping portion and the clamping base, the respective clamping forces exerted in multiple directions.