To obtain an ultrasonic flaw detection inspection apparatus which restricts generation of air bubbles at a transmission medium and enables detection of superior reliability.

The ultrasonic flaw detection inspection apparatus includes a container 8 storing a water 9 through which ultrasonic waves can be transmitted, a stage 10 which has a rotary shaft set perpendicularly to a horizontal face in the container 8, is soaked in the water 9 and driven to be rotated, and an ultrasonic probe 13 set in the water 9 for transmitting ultrasonic waves to a body 11 to be inspected via the water 9 and detecting reflecting waves, thereby confirming a state of the body 11 to be inspected. The body 11 to be inspected is loaded on an upper face of the stage. In the apparatus, an isolation wall 14 is installed in the water 9 to surround the periphery of the stage 10 and the body 11 to be inspected, which can be driven and rotated together with the stage 10 and the body 11 to be inspected 11.