To provide a RF circuit for a multi-band communication system and a multi-band antenna switch module optimum to a mobile phone adopting the combination of the CDMA system and the TDMA system.

The RF circuit for a multi-band communication system is provided with: a first filter circuit for passing a transmission signal of a transmission / reception system of the CDMA system emitted from a first antenna; a CDMA transmission section connected to the first filter circuit; a second filter circuit for passing a transmission / reception signal of a transmission / reception system of the first TDMA system emitted from the first antenna; a first switch circuit connected to the second filter circuit and for selecting the signal path of the transmission signal of the transmission system of the first TDMA system or the signal path of the reception signal of the transmission / reception system of the first TDMA system; a first TDMA transmission section connected to the first switch circuit; a first TDMA reception system connected to the first switch circuit; a third filter circuit for passing a reception signal of the transmission / reception system of the CDMA system emitted from the second antenna; and a CDMA reception section placed at the post-stage of the third filter circuit.