Abstract: A receiving filter of a SAW separator that prevents temperature increase, and enables to improve electric power-resisting property and attains high performance. A series arms and parallel arms of a transmitting filter and receiving filter are equipped with ladder type filters comprising SAW resonators. In the receiving filter, the number of pairs of finger electrodes of a parallel arm resonator P1 arranged at the first stage viewed from input side is larger than the number of pairs of finger electrodes of parallel arm resonators P2, . . . at other stages. Or interdigitated width of finger electrodes of the parallel resonator at the first stage is made longer than interdigitated width of finger electrodes of each of parallel resonators at other stages.