a filter having an improved frequency adjustment construction which is capable of conforming the frequencies of the resonators with better accuracy through improvements in the accuracy of the sizes of the electrodes used for frequency adjustment , and through better stabilizng of the filter characteristics through forming a positive connection between each electrode for adjustment use and the corresponding inner conductive film . electrodes for adjustment use are formed on a base plate , which is a separate unit from the dielectric block , so as to connect them with the respective resonators through coupling members , whereby the size accuracy of the electrodes for adjustment use is improved so as to considerably improve the frequency adjustment accuracy . also , the connection between the electrodes for adjustment use and the inner conductive films of the respective resonators is positively stabilized to improve the stability of the filter characteristics .