The purpose of the present invention is to improve signal modulation resolution. A coarse phase modulation element 62A modulates a signal into any of M1 (M1 is an arbitrary integer) patterns in a first range. Fine phase modulation elements 62B-1 through 62B-(k−1) respectively modulate the signal into any of M2 through Mk (M2 through Mk are arbitrary integers that are independent of each other and M1) patterns in a second range through k-th range (k is an integer of 2 or greater). A coarse DAC 61A and DACs 61B-1 through 61B-(k−1) perform control such that the second range through k-th range become narrower than the first range.