A complex antenna has a first antenna element and a second antenna element each connected at one end to a different feed point and connected to each other at the other end through a parallel resonant circuit. Each antenna element has the same resonant frequency as the parallel resonant circuit. A mobile phone has an antenna switch with a first port connected to the first antenna element, a second port connected to the second antenna element, and a third port that can be connected to one of the first port and the second port and switched therebetween. A signal processing unit causes the antenna switch to connect the third port to the first port or to the second port and detects a signal captured by one of the antenna elements from the output of the third port.