Duplexer and communication device

A branching filter comprising:

• a first filter configured to connect a common terminal to a first terminal and corresponding to a first passband;
• a second filter configured to connect the common terminal to a second terminal and corresponding to a second passband not overlapping the first passband;
• a third filter configured to connect a node disposed at a branch point to the second terminal and corresponding to the first passband;
• a fourth filter configured to connect the node to the first terminal and corresponding to the second passband;
• and
• a 180° phase shifter disposed closer to the first terminal than the first filter and the fourth filter are, or disposed closer to the second terminal than the second filter and the third filter are, the 180° phase shifter being configured to make phases of output signals from a path extending from the first terminal through the first filter and the second filter to the second terminal and a path extending from the first terminal through the fourth filter and the third filter to the second terminal opposite each other, the output signals being based on the same input signal to the paths.