A spatial position x′ of each ultrasonic transducer is accurately obtained for each probe in consideration of each edge transducer gap, and a delay time T(x′(n)) and a weighting coefficient W(x′(n)) are calculated on the basis of the position of each ultrasonic transducer. A control unit executes ultrasonic transmission/reception by using the calculated delay times and weighting coefficients to realize a suitable acoustic field with high deflection angle accuracy, small sidelobes, and the like as compared with the prior art.
