Ultrasonic diagnosis device

An ultrasonic diagnosis device comprising:

• wave transmitting means for synthesizing a first transmission wave signal for forming an ultrasonic beam having a center frequency ω1 and travelling towards a first focus in a near distance and a second transmission wave signal for forming an ultrasonic beam having a center frequency ω2 lower than said ω1 and travelling towards a second focus in the same direction as said first focus but in a far distance, and driving an ultrasonic element group disposed in an array, respectively;
• digital converting means for sampling reception signals obtained by detecting reflection echoes in said ultrasonic element group at a sampling frequency higher than a Nyquist frequency of an upper limit of a signal band, and converting said reception signals to digital signals, respectively;
• mixing means for multiplying said digital signals by reference signal having a frequency decreasing gradually from near said ω1 to near said ω2, respectively;
• accumulating means for accumulating the digital signals multiplied, a number of said digital signals accumulated being equal to a number of a plurality of samples;
• and
• wave reception focusing means for imparting a delay for aligning a phase difference peculiar to each of said ultrasonic elements to said digital signals accumulated, and adding said digital signals delayed.