An image processing apparatus comprising: a volume data generation unit configured to generate, based on ultrasonic data acquired by scanning a three-dimensional region in a subject having a contrast agent injected therein over a predetermined period, first volume data, second volume data and third volume data, the ultrasonic data including a harmonic component associated with a signal component from the contrast agent, the first volume data being data of a luminance value representing a spatial density of the contrast agent in each time phase in an analysis period and being generated by extracting the harmonic component from the ultrasonic data concerning the three-dimensional region over the analysis period in the predetermined period, the second volume data being generated from the first volume data and indicating contrast agent temporal information with respect to the luminance value about the analysis period, the contrast agent temporal information being one of an arrival time of the contrast agent at each position in the three-dimensional region, a peak time at which the luminance value becomes a maximum value, a Wash-In time, and a Wash-Out time, and the third volume data being generated from the first volume data and indicating a contrast agent characteristic amount with respect to the luminance value at each position in the three-dimensional region in the analysis period, the contrast agent characteristic amount being one of a maximum value of the luminance value, a minimum value of the luminance value, and an average value of the luminance value; an image generation unit configured to generate a projected image by executing projection processing using the second volume data and the third volume data, and a setting unit configured to set a projection range corresponding to a thickness in a depth direction that is to be a target of the projection processing, wherein the image generation unit assigns, using the set projection range, a color tone associated with the contrast agent temporal information and luminance associated with the contrast agent characteristic amount to each position in the three-dimensional region and generates the projected image having the thickness corresponding to the projection range by executing the projection processing to project the assignment result along a projection direction. a volume data generation unit configured to generate, based on ultrasonic data acquired by scanning a three-dimensional region in a subject having a contrast agent injected therein over a predetermined period, first volume data, second volume data and third volume data, the ultrasonic data including a harmonic component associated with a signal component from the contrast agent, the first volume data being data of a luminance value representing a spatial density of the contrast agent in each time phase in an analysis period and being generated by extracting the harmonic component from the ultrasonic data concerning the three-dimensional region over the analysis period in the predetermined period, the second volume data being generated from the first volume data and indicating contrast agent temporal information with respect to the luminance value about the analysis period, the contrast agent temporal information being one of an arrival time of the contrast agent at each position in the three-dimensional region, a peak time at which the luminance value becomes a maximum value, a Wash-In time, and a Wash-Out time, and the third volume data being generated from the first volume data and indicating a contrast agent characteristic amount with respect to the luminance value at each position in the three-dimensional region in the analysis period, the contrast agent characteristic amount being one of a maximum value of the luminance value, a minimum value of the luminance value, and an average value of the luminance value; an image generation unit configured to generate a projected image by executing projection processing using the second volume data and the third volume data, and a setting unit configured to set a projection range corresponding to a thickness in a depth direction that is to be a target of the projection processing, wherein the image generation unit assigns, using the set projection range, a color tone associated with the contrast agent temporal information and luminance associated with the contrast agent characteristic amount to each position in the three-dimensional region and generates the projected image having the thickness corresponding to the projection range by executing the projection processing to project the assignment result along a projection direction.