An electric signal transmission line includes a signal electrode portion (2), a ground electrode portion (3) and a dielectric portion (4) formed on a semiconductor substrate (1). The signal electrode portion (2) has a metal electrode (21) through which the electric signals flow, an upper conductive semiconductor (22) and a lower conductive semiconductor (23). The ground electrode portion (3) has a grounded metal electrode (31) and a conductive semiconductor (32). With the upper conductive semiconductor (22) and lower conductive semiconductor (23) having opposite polarities, the metal electrode (21) of the signal electrode portion 2 and the metal electrode (31) of the ground electrode portion (3) are connected with a semiconductor PN junction. A dielectric material fills and covers a region between the metal electrode (21) of the signal electrode portion (2) and the metal electrode (31) of the ground electrode portion (3) through which a line of electric force runs to form the dielectric portion (4). With this, it is possible to provide an electric signal transmission line that is capable of high-speed electric signal propagation and can be manufactured with stable quality using current semiconductor manufacturing processes.