An imaging apparatus and method for diagnosis acquiring information of an inside of a blood vessel and reconstructing a vascular image are disclosed, wherein when acquiring data through a rotation position and a movement of an imaging core, X-ray images at a fixed viewpoint position are synchronized so as to be continuously input along a time axis. Then, timing when vascular activity such as a cardiac beat can occur is determined based on the X-ray images. A plurality of vascular cross-sectional images on a plane orthogonal to a vascular axis acquired through the rotation and the movement of the imaging core are acquired. Then, a vascular image along the vascular axis is generated from the vascular cross-sectional image or the vascular cross-sectional images in series, and when performing a display, a site having vascular activity is displayed in a discriminable manner.
