Disclosed is a wearable electronic device that includes a strap detachably fastened to at least a part of a housing and including a plurality of unit links, a button operatively exposed from at least one of the plurality of unit links, a tension rib secured to an end portion of the button in an internal space of the unit link and having opposite ends that have positions that are 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, moving by means of the pressing of the button, are inserted into or extracted from pin-receiving recesses formed in an adjacent unit link.