Zipper head assembly structure and sliding element thereof

A zipper head assembly structure, comprising:

• a sliding element having a base portion, two lateral wall portions, and a seat portion, the two lateral wall portions respectively upwardly extended from two opposite lateral sides of the base portion, the two lateral wall portions corresponding to each other and connected to a front side of the base portion, the seat portion disposed on the base portion and connected to a back side of the base portion, the seat portion having a positioning passing hole formed between the two lateral wall portions, and the seat portion having a main body disposed on the base portion and connected to the back side of the base portion, two strip convex ribs respectively disposed on two opposite sides of the main body, and two concave spaces respectively connected to the two strip convex ribs;
• a retaining element movably disposed on the seat portion, wherein the retaining element has a positioning portion disposed on an end portion thereof and passing through the positioning passing hole;
• and
• a pulling element movably mated with the retaining element.