To enable to connect a coaxial cable with a circuit board without a specific work, and improve transmission of signal by preventing a short-circuit disturbance.

A coaxial cable connection jig connecting the coaxial cable 20 with a circuit board 10 has a horizontal member 31 consisting of an insulator and a vertical member 32. The coaxial cable 20 is inserted into a hole of this circuit board 10, and after a conductor 22 contacts the horizontal member 31, the conductor and a metal film of ground potential are insulated by electrically connecting the conductor by soldering and jointing the conductor to a signal wire 14a of a connecting pad 14.