A radio transmission apparatus capable of enhancing the diversity effect. In this apparatus, phase rotation section (102) performs phase rotation processing of 40.6.degree.=26.6.degree.+14.0.degree., interleavers (106,111) perform two-time interleaving processing before IQ combining processing performed in a combining section (107) and after IQ separation processing performed in an IQ separating section (108), and the original modulation symbol obtained in a mapping section (101) is thereby dispersed and mapped to/at signal points of M-ary modulation level higher two ranks or more (for example, from a QPSK symbol to 256QAM symbols).