A mechanism for adjusting the distance and relative horizontal level between a storage box lid and the product storage box body includes a rod, a first adjustment member, and a second adjustment member. The rod is positioned on the edge of the box and is axially movable. The first and second adjustment members on the rod can be repositioned along the length direction of the rod to increase or decrease the distance between the lid and the box body to accommodate different thicknesses of seals between the two, and for achieving integrity in a horizontal level. A product storage box is also disclosed.