A multiplexer includes a common terminal connected to an inductance element at a connection path with an antenna element, filter elements including different pass bands and connected to the antenna element with the common terminal therebetween, and an inductance element arranged in series between a transmission filter with a largest capacitance when viewed from the antenna side among the filter elements and the common terminal. An inductive component of the inductance element and a capacitive component of the transmission filter element define an LC series resonant circuit, and a resonant frequency of the LC series resonant circuit is lower than any of pass bands of the filter elements.