PURPOSE: To provide a transmitter where the primary modulation system in a spreaded spectrum signal is made the switching system of a two-phase modulation and an offset quadraple phase modulation and the receiver receiving this transmission.

CONSTITUTION: A two-phase modulation (BPSK) block is composed of a first differential conversion part 2, a first spectrum spread modulation part 3 and a first phase modulator 5, etc. An offset quadraple phase modulation (OQPSK) block is composed of the BPSK block, a second differential conversion part 8, a second spectrum spread modulation part 9, a delay circuit (offset) 10, a second phase modulator 11 and an adder 13, etc. In order to switch these BPSK and OQPSK, a first switching circuit 1, a second switching circuit 14 and a third switching circuit 15 are provided. At the time of the BPSK, the first switching circuit is turned an (a) side, and the second and third switching circuits are turned off. At the time of the OQPSK, the first switching circuit is turned a (b) side, and the second and third switching circuits are turned on. For the OQPSK, a data array conversion part 7 converting data from serial data to parallel data is provided.