A cord lock includes a female member having a first opening, a second opening, an insertion path for a string therebetween, and female-side fastening portions formed in the insertion path, a male member having one portion entering into the insertion path from a side of the first opening, and male-side fastening portions at the one portion adapted to be fastened to the string inserted to pass through the insertion path in cooperation with the female-side fastening portions, and a spring member interposed between the female member and the male member. The fastening relative to the string is released by a pulling operation of reducing an entering amount of the one portion of the male member into the insertion path. A first contact portion of the spring member is integrally formed with the female member, and a second contact portion of the spring member is integrally formed with the male member.