An electronic device may include a main body including a front plate, a rear plate disposed to be spaced apart from the front plate, a lateral member surrounding a space between the front plate and the rear plate, and a display viewed through at least a portion of the front plate. The electronic device may further include a housing having a space therein and combined with a strap at one side thereof in a first axial direction, a first fastening part protruding from another side of the housing toward the main body and detachably connected to the main body, a second fastening part formed in the main body and engaged with the first fastening part, and a button disposed in the housing, exposed at least in part to an outside of the housing, and moving the first fastening part to be separated from the second fastening part.