Slide fastener

A slide fastener, comprising:

• a plurality of fastener units, each of the plurality of fastener units including
• fastener tapes comprising elements which are arranged in a line along oppositely-faced edges of opening/closing ends of the fastener tapes, each of the elements comprising
• a horizontal section having a meshing portion on one side and a fastener-tape fixed portion on the other side, in the horizontal direction,
• an upper vertical section having an engagement piece extending perpendicularly upwards from the meshing portion of the horizontal section, and
• a lower vertical section having an engagement holding piece extending perpendicularly downwards from the fastener-tape fixed portion of the horizontal section, and
• a slider in which the elements are arranged to oppositely face each other and in which the meshing portions of the elements are meshed with each other by sliding the slider between oppositely-faced elements, whereby the engagement pieces of the oppositely-faced elements form an engagement portion and the engagement holding pieces of the oppositely-faced elements form an engagement holding portion,
• wherein the plurality of fastener units are multilayered such that the engagement holding portions of a first fastener unit among said plurality of fastener units can be engaged with the engagement portions of a second fastener unit among said plurality of fastener units, and wherein the engagement holding portions of a third fastener unit can be engaged with the engagement portions of the second fastener unit, whereby the engagement portions of the plurality of fastener units are formed in succession.