To reduce the transmission loss and to make the module small in size by connecting 1st and 2nd high frequency printed circuit boards with a transmission line interconnecting the 1st and 2nd high frequency printed circuit boards with a small transmission loss at the shortest distance.

A frequency conversion section 13 is placed on a 1st high frequency printed circuit board 10. Furthermore, a hollow coaxial line 20 is arranged perpendicularly between the 1st high frequency printed circuit board 10 and a 2nd high frequency printed circuit board 30 placed nearly in parallel with the 1st high frequency printed circuit board 10. The hollow coaxial line 20 is used to connect the 1st high frequency printed circuit board 10 and the 2nd high frequency printed circuit board 30. After the frequency conversion section 13 placed on the 1st high frequency printed circuit board 10 converts a high frequency signal into an intermediate frequency signal, the signal is sent to the 2nd high frequency printed circuit board 30 via the hollow coaxial line 20. Moreover, the video signal conversion section 33 is placed on the 2nd high frequency printed circuit board 30 which converts the received intermediate frequency signal into a video signal.