This invention provides a technique to dynamically set an imaging parameter appropriate for observing a region of interest on an object to generate a high-quality echogram while maintaining the operability to change the position and orientation of a probe. A region-of-interest acquisition unit acquires region information that defines the region of interest. A position and orientation acquisition unit acquires position and orientation information representing the position and orientation of a probe. A parameter deciding unit obtains an imaging parameter based on the positional relationship between an imaging range decided based on the position and orientation information and the region of interest defined by the region information, and outputs the obtained imaging parameter to an imaging unit.
