A multiplexer comprising: a number n, n being a natural number of 3 or larger, of band pass filters (10-40) having a number n or larger of mutually different pass bands; and a common terminal commonly provided for the number n of band pass filters (10-40), characterized in that , among the number n of band pass filters (10-40), for a first band pass filter that is either a band pass filter having a center frequency of a pass band at a lowest frequency side out of the n band pass filters or a band pass filter having a center frequency of a pass band at a highest frequency side out of the n band pass filters and that has a larger or equal difference in a center frequency of a pass band from an adjacent band pass filter as compared with the other band pass filter at the other of the highest or lowest frequency side, wherein f is the center frequency of the pass band of the first bandpass filter and B is a susceptance value of the first bandpass filter viewed from the common terminal, and among the number n of band pass filters, for a second band pass filter which is the adjacent bandpass filter having a pass band adjacent to the first band pass filter, wherein f is the center frequency of the pass band of the second bandpass filter and B is a susceptance value of the second bandpass filter viewed from the common terminal, the first band pass filter satisfies one of a condition (i) and a condition (ii) with respect to the second band pass filter as follows: (i) B ×{2×f -f }/f < B < B if the first band pass filter is the band pass filter at the highest frequency side, and (ii) B < B < B ×{2×f -f }/f if the first band pass filter is the band pass filter at the lowest frequency side. a number n, n being a natural number of 3 or larger, of band pass filters (10-40) having a number n or larger of mutually different pass bands; and a common terminal commonly provided for the number n of band pass filters (10-40), characterized in that , among the number n of band pass filters (10-40), for a first band pass filter that is either a band pass filter having a center frequency of a pass band at a lowest frequency side out of the n band pass filters or a band pass filter having a center frequency of a pass band at a highest frequency side out of the n band pass filters and that has a larger or equal difference in a center frequency of a pass band from an adjacent band pass filter as compared with the other band pass filter at the other of the highest or lowest frequency side, wherein f is the center frequency of the pass band of the first bandpass filter and B is a susceptance value of the first bandpass filter viewed from the common terminal, and among the number n of band pass filters, for a second band pass filter which is the adjacent bandpass filter having a pass band adjacent to the first band pass filter, wherein f is the center frequency of the pass band of the second bandpass filter and B is a susceptance value of the second bandpass filter viewed from the common terminal, the first band pass filter satisfies one of a condition (i) and a condition (ii) with respect to the second band pass filter as follows: (i) B ×{2×f -f }/f < B < B if the first band pass filter is the band pass filter at the highest frequency side, and (ii) B < B < B ×{2×f -f }/f if the first band pass filter is the band pass filter at the lowest frequency side. (i) B ×{2×f -f }/f < B < B if the first band pass filter is the band pass filter at the highest frequency side, and (ii) B < B < B ×{2×f -f }/f if the first band pass filter is the band pass filter at the lowest frequency side. <EOS>