Abstract: A one-touch type coupler for longitudinally interconnecting iron bars of the present disclosure includes a coupler housing, on both sides of which an iron bar fitting hole into which an iron bar is inserted is formed; a spring member, one side of which is seated on the inside of the iron fitting hole to apply elastic force and the radius of which is decreased gradually toward the insertion direction of the iron bar; a propping member which is seated on an upper end of the spring member and is composed of a seating part introduced toward an inner side of the spring member and a seating surface extending toward the outer radial direction from the upper circumference of the seating part by a predetermined length; a plurality of joining pieces which are seated on the propping member to surround the iron bar inserted into the inside of the iron bar fitting hole and a tapered first inclined surface is formed on an outer peripheral surface thereof; and a coupler cap, on the inside of which a tapered second inclined