An electronic device and a system including the same are disclosed. An electronic device of the present invention includes: a body; a plurality of supports each of which is coupled to the body through one side thereof; and a holder configured to connect other sides of the plurality of supports having a curved portion corresponding to the shape of the ear of a user and fitted in the ear of the user, wherein at least one of the plurality of supports rotates on the body, wherein the radius of the holder is changed according to rotation of the at least one of the plurality of supports. According to the present invention, the supports coupled to the body rotate to be fixed to the user's ear.