A Pseudorandom Noise (PN) code generating circuit includes a shift register, an adding circuit for exclusive-ORing tap output data of the shift register and feed-back output data of the shift register, selectors disposed as upstream circuits of each register composing the shift register, phase designating circuits for selectively obtaining tap output data of the shift register corresponding to mask data for designating the phase of the PN code, and a data storing device for storing the initial data and the mask data. When the initial data is set to the shift register, the initial data is stored in the data storing device and the initial data is set to each register of the shift register through the selectors. When the PN code is generated, the selectors send data stored in each register of the shift register so as to generate the PN code and the data storing device stores the mask data. Tap output data of the shift register is selectively obtained corresponding to the mask data.