In the nuclear medicine imaging apparatus according to the one embodiment, the ADC converts the output data of each of the photodetectors to digital data. The counting information collecting unit collects counting results from the digital data, and the counting information storage unit stores the counting result in association with the digital data. The coincidence counting information generating unit generates coincidence counting information. The image reconstructing unit reconstructs a PET image, based on the coincidence counting information. The time correction data stores a correction time for each of the photodetectors. The system controlling unit controls to correct the detection time of the gamma rays in the digital data associated with each piece of the counting information by use of the correction time, and to generate new coincidence counting information. The system controlling unit controls to reconstruct a new nuclear medicine image, based on the new coincidence counting information generated.