According to one embodiment, a position detection unit detects position information of an ultrasonic probe including ultrasonic transducers, with reference to a reference position. A transmission/reception unit supplies a driving signal to each transducer and generates a reception signal based on a reception echo signal generated by the transducer. Based on the reception signal, a three-dimensional data generation unit generates first three-dimensional data, in which a region corresponding to a living body tissue is specified by a specifying unit. A setting unit sets a first viewpoint based on the position information and specified region. An image generation unit generates a rendering image by rendering processing using the first viewpoint and first three-dimensional data.