PURPOSE: To improve the filter characteristics with deletion of the high frequency component by installing the pre-filter formed by integration of the MOS transistor and the capacitor plus the transversal filterformed by CTD and connected vertically to the pre-filter.

CONSTITUTION: The 1st resistance circuit comprising MOS transistors TrM1 and M2 plus capacitor C1, the 2nd resistance circuit consisting of TrM3 and M4 plus capacitor C12, and the 3rd resistance circuit comprising TrM5 and M6 plus capacitor C13 are provided each to the front-step circuit of the pre-filter. And buffers A1 and A2 are formed with TrM9 and M10 plus M11 and M12 respectively. Furthermore, the rear-step 4th resistance is formed with TrM7 and M8 plus capacitor C14 respectively. Then main filter part F composed of CTD is connected to the output of such pre-filter. Thus the high frequency component is deleted by the pre-filter, improving the overall filter characteristics.