An electronic device comprising: a housing including a front plate, a rear plate facing an opposite direction to the front plate, and a side member surrounding a space between the front plate and the rear plate and including a conductive annular member; at least one mounting member (395, 397) connected to the side member and detachably mounted on a portion of a human body such that the rear plate faces the portion of the human body; a substrate, PCB, disposed in the space in parallel with the front plate and having a ground plane; at least one wireless communication circuit disposed on the substrate; characterised in that the electronic device comprises: a first electrical path connected between the wireless communication circuit and a first point of the conductive annular member; a second electrical path connected between the ground plane and a second point of the conductive annular member in which a first region of the conductive annular member defined between the first point and the second point has a first length and a second region of the conductive annular member defined between the first point and the second point has a second length smaller than the first length; and a conductive pattern disposed in the space, having an extension that extends along a portion of the first region or the second region of the annular member, and electrically connected to the wireless communication circuit. a housing including a front plate, a rear plate facing an opposite direction to the front plate, and a side member surrounding a space between the front plate and the rear plate and including a conductive annular member; at least one mounting member (395, 397) connected to the side member and detachably mounted on a portion of a human body such that the rear plate faces the portion of the human body; a substrate, PCB, disposed in the space in parallel with the front plate and having a ground plane; at least one wireless communication circuit disposed on the substrate; characterised in that the electronic device comprises: a first electrical path connected between the wireless communication circuit and a first point of the conductive annular member; a second electrical path connected between the ground plane and a second point of the conductive annular member in which a first region of the conductive annular member defined between the first point and the second point has a first length and a second region of the conductive annular member defined between the first point and the second point has a second length smaller than the first length; and a conductive pattern disposed in the space, having an extension that extends along a portion of the first region or the second region of the annular member, and electrically connected to the wireless communication circuit. a first electrical path connected between the wireless communication circuit and a first point of the conductive annular member; a second electrical path connected between the ground plane and a second point of the conductive annular member in which a first region of the conductive annular member defined between the first point and the second point has a first length and a second region of the conductive annular member defined between the first point and the second point has a second length smaller than the first length; and a conductive pattern disposed in the space, having an extension that extends along a portion of the first region or the second region of the annular member, and electrically connected to the wireless communication circuit.