PURPOSE: To easily attain very thin profile and short length and to change linearly the attenuation of a control voltage.

CONSTITUTION: The device is provided at least with a 1st ground pattern 3a corresponding to a 1st high frequency integrated circuit 11a, a 2nd high frequency integrated circuit 11b corresponding to a 2nd ground pattern 3b which are formed respectively to major sides of a circuit board main body 4 opposite to each other, and the high frequency integrated circuits 11a, 11b are isolated by the ground patterns 3a, 3b or the like formed opposing each other. Thus, electronic components of each high frequency integrated circuit are effectively isolated, the electromagnetic coupling among the electronic components is reduced or eliminated, a defect such as parasitic vibration or oscillation or the like is eliminated and the attenuation of control voltage is easily changed linearly.