1. A medical image processing unit comprising: a volume data input unit for inputting three-dimensional volume data from a modality; a volume rendering unit for generating a two-dimensional rendered image by converting the three-dimensional volume data, which is input to the volume data input unit, into two-dimensional volume data; a depth information generator for generating depth information indicative of length from a virtual view position in a virtual three-dimensional space to the three-dimensional volume data on the basis of the three-dimensional volume data which is input to the volume data input unit; an anti-aliasing unit for identifying a target in the rendered image generated by the volume rendering unit based on the depth information generated by the depth information generator and executing anti-aliasing processing on an edge portion of the identified target; and a display unit for displaying an image including the target, on which the anti-aliasing processing has been executed, as a rendered image.