MULTIPLEXER, HIGH FREQUENCY FRONT END CIRCUIT, AND COMMUNICATION DEVICE

A multiplexer (1) comprises: a transmission-side filter (11) connected to a common terminal (90) and a transmission input terminal (91); and a reception-side filter (12) connected to the common terminal (90) and a reception output terminal (92). The transmission-side filter (11) comprises a plurality of series arm resonators (101-104); a plurality of parallel arm resonators (201, 202); and a parallel arm circuit (203). In an IDT electrode of the series arm resonator (101) which is connected closest to the common terminal (90), the electrode finger pitch in the arrangement-direction central part of a plurality of electrode fingers is the greatest among the electrode finger pitches of the IDT electrode, and the electrode finger pitch at the arrangement-direction ends is the smallest among the electrode finger pitches of the IDT electrode. 多工器(1)具备与共同端子(90)及发送输入端子(91)连接的发送侧滤波器(11)以及与共同端子(90)及接收输出端子(92)连接的接收侧滤波器(12)，发送侧滤波器(11)具备多个串联臂谐振器(101～104)、以及多个并联臂谐振器(201，202)及并联臂电路(203)，在最靠近共同端子(90)而连接的串联臂谐振器(101)所具有的IDT电极中