An electronic device (40) includes a transmitter substrate (43) for generating information to be measured by a sensor (50) arranged in a partitioned space (10) which is partitioned by a tyre (1) and a rim wheel (2), a signal line (45) extended from the transmitter subs/rate (43)to outside of the partitioned space (10) and passing through an inner side of an air valve (30) provided at the rim wheel (2), the signal line (45) being formed by a core wire (45a) made of a conductor and a coaxial cable (45b) covering that core wire (45a), and an antenna (47) for transmitting radio waves containing the information (such as information of the tyre 1) generated by that transmitter substrate (43), the antenna (47) being connected to the signal line (45) and positioned outside the air valve (30).