A portable wireless LAN terminal device attachable to an external connecting terminal installed in a portable external connection device, such as a portable data terminal device, includes a device body (2); means for transmitting and receiving (6-9) a signal through a wireless LAN circuit, the means for transmitting and receiving being installed the device body (2); means for supplying power (11) to each portion from means for accumulating power installed in the device body (2) or means for accumulating power attachable to the device body (2); a connecting terminal (13) installed in the device body (2) and attachable to the external connecting terminal; and first sound producing means (12, 15), which is installed in the device body, for producing sound based on the signal received by the means for transmitting and receiving (6-9).