A wireless terminal unit for wireless communications, the wireless terminal unit comprising: a wireless circuit board; first and second antenna elements (404, 405) facing one of surfaces of the wireless circuit board; and a plurality of ground terminals (407, 408, 409) electrically connecting the wireless circuit board with a ground conductor, wherein the ground conductor facing and being parallel to the other surface of the wireless circuit board, wherein the ground conductor is a sheet metal made of a conductor, the first antenna element is orthogonal to a plane of the wireless circuit board, wherein one end of the first antenna element is electrically connected with the wireless circuit on the wireless board and the other end of the first antenna element faces and is parallel to the circuit board, the second antenna element is orthogonal to the plane of the wireless circuit board, wherein one end of the second antenna element is electrically connected with the wireless circuit on the wireless circuit board and the other end of the second antenna element faces and is parallel to the circuit board, and the first and second antenna elements (404, 405) are L-shaped linear conductors; characterized in that: the wireless circuit board has a perimeter that is more than or equal to 1⁄2 wavelength and less than or equal to 1 wavelength at an operating frequency; a first ground terminal, one of the plurality of ground terminals (407, 408, 409), is disposed near a power supply part for supplying power from the wireless circuit board to the first antenna element, and a second ground terminal, one of the plurality of ground terminals (407, 408, 409), is disposed near a power supply part for supplying power from the wireless circuit board to the second antenna element; the first ground terminal is arranged at one end of the wireless circuit board, and the second ground terminal is arranged at the opposite end of the wireless circuit board. a wireless circuit board; first and second antenna elements (404, 405) facing one of surfaces of the wireless circuit board; and a plurality of ground terminals (407, 408, 409) electrically connecting the wireless circuit board with a ground conductor, wherein the ground conductor facing and being parallel to the other surface of the wireless circuit board, wherein the ground conductor is a sheet metal made of a conductor, the first antenna element is orthogonal to a plane of the wireless circuit board, wherein one end of the first antenna element is electrically connected with the wireless circuit on the wireless board and the other end of the first antenna element faces and is parallel to the circuit board, the second antenna element is orthogonal to the plane of the wireless circuit board, wherein one end of the second antenna element is electrically connected with the wireless circuit on the wireless circuit board and the other end of the second antenna element faces and is parallel to the circuit board, and the first and second antenna elements (404, 405) are L-shaped linear conductors; characterized in that: the wireless circuit board has a perimeter that is more than or equal to 1⁄2 wavelength and less than or equal to 1 wavelength at an operating frequency; a first ground terminal, one of the plurality of ground terminals (407, 408, 409), is disposed near a power supply part for supplying power from the wireless circuit board to the first antenna element, and a second ground terminal, one of the plurality of ground terminals (407, 408, 409), is disposed near a power supply part for supplying power from the wireless circuit board to the second antenna element; the first ground terminal is arranged at one end of the wireless circuit board, and the second ground terminal is arranged at the opposite end of the wireless circuit board. the wireless circuit board has a perimeter that is more than or equal to 1⁄2 wavelength and less than or equal to 1 wavelength at an operating frequency; a first ground terminal, one of the plurality of ground terminals (407, 408, 409), is disposed near a power supply part for supplying power from the wireless circuit board to the first antenna element, and a second ground terminal, one of the plurality of ground terminals (407, 408, 409), is disposed near a power supply part for supplying power from the wireless circuit board to the second antenna element; the first ground terminal is arranged at one end of the wireless circuit board, and the second ground terminal is arranged at the opposite end of the wireless circuit board.