A coordinate input device including a coordinate sensor and a wireless communication circuit that wirelessly transmits coordinate data, etc. to an external electronic device is realized without affecting coordinate detection by the coordinate sensor and without impeding downsizing of the coordinate input device. A shield sheet (1C) is provided to cover the whole of a surface (back surface) of a sensor (1B) opposite to a sensor input surface (front surface) facing an electronic pen. A controller (200) that controls transmission of the coordinate data detected by the sensor (1B) to the external electronic device is disposed facing the sensor (1B) with the shield sheet (1C) disposed between the sensor and the controller, and a transmission antenna connected with the controller (200) is arranged outside a region covered with the shield sheet (1C).