An electronic device includes a housing including a front surface plate, a rear surface plate facing a direction opposite the front surface plate, and a side surface member surrounding a space between the front surface plate and the rear surface plate; at least one attachment member coupled to the side surface member, and removably fastened to a human body, the at least one attachment member including a first attachment member coupled to at least part of the side surface member, and a second attachment member coupled to a position of the side surface member facing the first attachment member; a substrate arranged in the space in parallel with the front surface plate; at least one wireless communication circuit arranged on the substrate; a first conductive pattern electrically connected with the wireless communication circuit, and arranged on the side surface member in proximity to the first attachment member; a second conductive pattern arranged on the side surface member in proximity to the second attachment member; a first conductive member arranged in the first attachment member in proximity to the first conductive pattern to be capacitively coupled with the first conductive pattern; and a second conductive member arranged in the second attachment member in proximity to the second conductive pattern to be capacitively coupled with the second conductive pattern.