Photon-counting type X-ray CT apparatus

Provided is a photon-counting type X-ray CT apparatus according to embodiments including a detector, a first collecting unit, a second collecting unit, and an image reconstruction unit. The detector detects an X-ray and outputs a signal. The first collecting unit collects count data of photons of the X-ray for every energy band with a predetermined time width by using the signal output from the detector. The second collecting unit corrects integration data obtained by integrating the signal with the predetermined time width by using the signal output from the detector. The image reconstruction unit corrects the count data by using the integration data. The image reconstruction unit generates a reconstructed image by performing a reconstructing process on the corrected count data.