A cord lock comprising: a male tool; and a female tool that receives a part of the male tool by pressing the male tool against a biasing force of a biasing means so as to match cord eyelets (13, 22) formed in sides of the male tool and the female tool each other at a predetermined pressing position of the male tool, wherein an engaging part that is engaged with an engaged part of the female tool by the biasing force of the biasing means to prevent the male tool from slipping out of a position before the pressing operation, is formed on a side of the male tool, said engaging part being a protrusion protruding outward from the side of the male tool in a direction intersecting a direction in which the eyelets (13, 22) pass through, and at a position closer to a pressing backward side (Bw) than a hole edge located on a pressing forward side (Fw) of the eyelet, wherein a sectional outer shape of the male tool in a direction orthogonal to a pressing direction (x) complements an inner shape of the female tool, and an outline of the male tool on one side halved by a virtual straight line (z) passing a center (y) of the male tool constituting the sectional outer shape, and an outline on the other side are symmetrical relative to the center of the male tool, a side of the female tool has a communicating part that communicates from an inside to an outside of the female tool, and a part of the side of the female tool located between the communicating part and an upper surface of the female tool on the pressing backward side (Bw) of the male tool constitutes an elastically deformable engaged part, wherein the male tool can be combined with the female tool only in the state where the side having the eyelets is located on the side of the side having the eyelets of the female tool, and the side having the engaging part is located on the side of the side having the engaged part of the female tool, simplifying assembling of the male tool and the female tool, characterized in that the biasing means is formed of a compression coil spring configured to have a smaller spring diameter as it comes closer from the spring upper end to the spring lower end, wherein a band-like hanging part formed of a shoulder part extending from a side surface having the eyelets is provided on the outer side of the side surface of the female tool, on which the communication part is formed. a male tool; and a female tool that receives a part of the male tool by pressing the male tool against a biasing force of a biasing means so as to match cord eyelets (13, 22) formed in sides of the male tool and the female tool each other at a predetermined pressing position of the male tool, wherein an engaging part that is engaged with an engaged part of the female tool by the biasing force of the biasing means to prevent the male tool from slipping out of a position before the pressing operation, is formed on a side of the male tool, said engaging part being a protrusion protruding outward from the side of the male tool in a direction intersecting a direction in which the eyelets (13, 22) pass through, and at a position closer to a pressing backward side (Bw) than a hole edge located on a pressing forward side (Fw) of the eyelet, wherein a sectional outer shape of the male tool in a direction orthogonal to a pressing direction (x) complements an inner shape of the female tool, and an outline of the male tool on one side halved by a virtual straight line (z) passing a center (y) of the male tool constituting the sectional outer shape, and an outline on the other side are symmetrical relative to the center of the male tool, a side of the female tool has a communicating part that communicates from an inside to an outside of the female tool, and a part of the side of the female tool located between the communicating part and an upper surface of the female tool on the pressing backward side (Bw) of the male tool constitutes an elastically deformable engaged part, wherein the male tool can be combined with the female tool only in the state where the side having the eyelets is located on the side of the side having the eyelets of the female tool, and the side having the engaging part is located on the side of the side having the engaged part of the female tool, simplifying assembling of the male tool and the female tool, characterized in that the biasing means is formed of a compression coil spring configured to have a smaller spring diameter as it comes closer from the spring upper end to the spring lower end, wherein a band-like hanging part formed of a shoulder part extending from a side surface having the eyelets is provided on the outer side of the side surface of the female tool, on which the communication part is formed.