PURPOSE: To realize radio transmission acting like space diversity even with one reception antenna.

CONSTITUTION: Serial transmission data are coded into a (n, k) block code by a data coding means 12 and a data conversion means 3 is used to convert the data into parallel data by n-bit each. A data modulation means 13 is used to modulate the data into n-sets of carriers whose frequencies are discrete to each other and each of data transmission means 14 makes radio transmission from n-sets of positions apart by a distance of 1/4 of each wavelength individually. Since the n-sets of carriers sent as radio waves in this way have different propagation paths, the fading characteristic differs and the plural carriers are complemented by error correction, then the same function as the space diversity is realized.