Provided is a broadband internal antenna including a ground plate and an antenna unit. The antenna unit can include a feed point; a first radiator, formed with a bar shape having the feed point as one end part and the other end part from which an uncurved ‘C’ shape is extended; a ground point, connected to the ground plate; a second radiator, having one end part on which the ground point is mounted and the other end part that is connected to an area from which the uncurved ‘C’ shape of the first radiator starts to be formed in an open loop form; a first protrusion part, protruded from the uncurved ‘C’ shape of the first radiator to be formed in a closed loop form; and a second protrusion part, formed inside the open loop shape of the first radiator in an inverse L’ form.