An ultrasonic inspection method of scanning and inspecting an inspection object with ultrasonic waves includes collecting data obtained by scanning the inspection object with ultrasonic signals by using probes configured to transmit and receive the ultrasonic signals to and from the inspection object via a medium that propagates the ultrasonic signals; and processing and synthesizing the collected data. Synthesizing the data includes depicting an image including a surface of the inspection object in a region including pixels partitioned in a grid-like fashion based on the collected data of the ultrasonic signals, and extracting a pixel having maximum pixel intensity from the pixels arranged along a direction perpendicular to an extending direction of the surface of the inspection object in the depicted image to identify a position of the extracted pixel as a surface shape of the inspection object.