A semiconductor device interconnecting unit configured to input/output a high-frequency signal having a millimeter wave band to/from a semiconductor device is provided. The semiconductor or device interconnecting unit includes a part of a band pass filter configured to pass therethrough the high-frequency signal having a millimeter wave band by using an LC resonance circuit, and a remainder of the band pass filter, wherein the part and the remainder are separated from each other. The part is provided inside the semiconductor device, and the remainder is provided outside the semiconductor device. The part and the remainder include capacitors having variable capacitors added thereto, respectively. A pass band for the high-frequency signal having a millimeter wave band is changed by changing capacitance values of the variable capacitors.