To provide a reference signal generation method and apparatus capable of obtaining many reference signal sequences having excellent properties. CAZAC sequences that satisfy the condition that the absolute value (|N−L|) of a difference between a sub-carrier number N in a resource block and a CAZAC sequence length L is not larger than a threshold value K are selected, and a sequence having a largest among greatest prime factors among the prime factors constituting the sequence length(s) is further selected from the initially selected sequences. Then, a reference signal sequence(s) is generated from a selected CAZAC sequence.