A wearable electronic device comprising: a housing ; and a strap detachably fastened to at least a part of the housing , wherein the strap comprises: a plurality of unit links ; a button exposed from at least one of the plurality of unit links so as to be operable; a tension rib, secured to an end portion of the button at a rib-fixing protrusion of the button , in an internal space of the unit link and having opposite ends, the positions of the opposite ends being changed by pressing of the button ; and a hinge pin secured to each of the opposite ends of the tension rib , and disposed to at least partially protrude from left and right sides of each of the unit links , wherein the plurality of unit links are fastened to or separated from each other, such that the hinge pins of a unit link , are inserted into, moving by means of the releasing of the button , or extracted from, moving by means of the pressing of the button , pin-receiving recesses formed in an adjacent unit link, the wearable electronic device is characterized in that , the tension rib is supported by a pair of rib-stopping pieces protruding beyond the bottom of a button-receiving space of the unit link and arranged such that the tension rib is deformed by the pressing of the rib-fixing protrusion and the support of the rib stopping pieces . a housing ; and a strap detachably fastened to at least a part of the housing , wherein the strap comprises: a plurality of unit links ; a button exposed from at least one of the plurality of unit links so as to be operable; a tension rib, secured to an end portion of the button at a rib-fixing protrusion of the button , in an internal space of the unit link and having opposite ends, the positions of the opposite ends being changed by pressing of the button ; and a hinge pin secured to each of the opposite ends of the tension rib , and disposed to at least partially protrude from left and right sides of each of the unit links , wherein the plurality of unit links are fastened to or separated from each other, such that the hinge pins of a unit link , are inserted into, moving by means of the releasing of the button , or extracted from, moving by means of the pressing of the button , pin-receiving recesses formed in an adjacent unit link, the wearable electronic device is characterized in that , the tension rib is supported by a pair of rib-stopping pieces protruding beyond the bottom of a button-receiving space of the unit link and arranged such that the tension rib is deformed by the pressing of the rib-fixing protrusion and the support of the rib stopping pieces . a plurality of unit links ; a button exposed from at least one of the plurality of unit links so as to be operable; a tension rib, secured to an end portion of the button at a rib-fixing protrusion of the button , in an internal space of the unit link and having opposite ends, the positions of the opposite ends being changed by pressing of the button ; and a hinge pin secured to each of the opposite ends of the tension rib , and disposed to at least partially protrude from left and right sides of each of the unit links , wherein the plurality of unit links are fastened to or separated from each other, such that the hinge pins of a unit link , are inserted into, moving by means of the releasing of the button , or extracted from, moving by means of the pressing of the button , pin-receiving recesses formed in an adjacent unit link, the wearable electronic device is characterized in that , the tension rib is supported by a pair of rib-stopping pieces protruding beyond the bottom of a button-receiving space of the unit link and arranged such that the tension rib is deformed by the pressing of the rib-fixing protrusion and the support of the rib stopping pieces . <EOS>