The invention discloses zipper teeth of a novel firmly-meshed zipper. Each zipper tooth comprises a tooth head, a tooth neck and a tooth tail, wherein the tooth head, the tooth neck and the tooth tail are sequentially connected. For each tooth, the tooth head is provided with an outer tooth head and an inner tooth head, the tooth neck is provided with an outer tooth neck and an inner tooth neck, the tooth tail is provided with an outer tooth tail and an inner tooth tail, the outer tooth head, the outer tooth neck and the outer tooth tail form an outer tooth, the inner tooth head, the inner tooth neck and the inner tooth tail form an inner tooth, and the outer tooth head is diminished from inside to outside. The invention further discloses the zipper with the zipper teeth. According to the zipper teeth and the zipper with the zipper teeth, due to the fact that each outer tooth neck is diminished from inside to outside, a recession space can be formed when the zipper is closed and bends outwards, the outer teeth will not be abutted, disturbing force making the meshed zipper teeth disengage can be prevented, and therefore meshing stability of the zipper in an outward-bending state can be improved. Due to the fact that each outer tooth neck is diminished from inside to outside, the closed zipper can bend outwards more easily, the radius of the bending portion is small, and the closed zipper can be smoother, more fitted and suitable for high-grade products like high-grade clothes.