PURPOSE: To provide an ultrasonic wave diagnosing system which permits the independent access to the write-in and read-out and the random access in read- out and is equipped with a frame memory part which operates at a low speed and is manufactured inexpensively.

CONSTITUTION: The image information obtained through an ultrasonic wave contact 1, signal processing part 2, and an A/D conversion part 3 is stored into a FIFO memory 4 for the small-scale waiting the forestage of a frame memory 5. The image information is stored into the frame memory 5 from the FIFO memory 4, averting the period for reading out the image information from the frame memory 5. The image information read out from the frame memory 5 is converted to the standard TV signal by an image processing part 6, and displayed on an observation monitor 7. When the access to the frame memory 6 is divided to the image output period and other period, the random access in reading-out is enabled.