PURPOSE: To reduce the production cost, by covering a tape containing a pair of the conductor storing longitudinal groove of the lengthwise direction and the conductor crossing lateral groove of a certain pitch with a dielectric sheath.

CONSTITUTION: A pair of the lengthwise grooves 14 for storing conductors and the lateral grooves 15 of a certain pitch provided across the conductor are formed to a dielectric tape 10. Then a dielectric tape 11 and a dielectric plate material 13 are stuck to the tape 10 to obtain a grooved tape. A conductor 16, i.e., a coated core wire of a transmission line is made to cross both grooves 14 and 15 with a certain pitch. A dielectric tape 12 is stuck onto the tape with grooves to which a pair of conductors so that the conductor pair does not get out of the grooves 14 and 15. The tape 10 has a certain degree of rigidity so as to keep the width and the form of the conductor pair, and accordingly the uniform transmission characteritics is secured for the transmission line with high accuracy secured for detection of the position. Furthermore, the tape 10 is required to have the sufficient strength against the tension caused during the production.