To reduce a burden on hardware for driving a two-dimensional (2D) array ultrasonic probe having a number of vibrators.

The ultrasonic diagnostic device is provided with programmable gain amplifiers a00-a99 for amplifying signal voltages e00-e99 from the vibrators of the 2D array ultrasonic probe, voltage/current converters h00-h99 for converting the voltages to current signals i00-i99, a matrix switch M for dividing the current signals i00-i99 into groups, adding the current signals in each group and respectively outputting added current signals I0-I9, current/voltage converters H0-H9 for converting the currents to voltage signals, programmable gain amplifiers A0-A9, A/D converters C0-C9, and a digital beam former unit B for outputting a sound ray signal W by performing reception beam forming while using digital signals D0-D9.