An apparatus for inspecting a pipe , comprising a pipe inspecting apparatus and a plurality of ultrasonic optical probes , each of which includes an ultrasonic transducer configured to input an ultrasonic wave to the pipe, and an optical fiber sensor configured so that laser light transmits through the optical fiber sensor, wherein the ultrasonic optical probes are attached at intersections of first lines (L1) extending in a first direction on a surface of the pipe and second lines (L2) extending in a second direction on the surface of the pipe; the pipe inspecting apparatus comprising: a power supplying module configured to supply power to the ultrasonic optical probes; a light source configured to generate the laser light and supply the laser light to the ultrasonic optical probes; a light detection module configured to detect the laser light from the ultrasonic optical probes; and a selection module configured to select an ultrasonic optical probe; characterized in that the selection module is configured to select, from the plurality of ultrasonic optical probes attachable to the pipe, a first ultrasonic optical probe to input the ultrasonic wave to the pipe, and a second ultrasonic optical probe to be supplied with the laser light; the power supplying module is configured to supply the power to the ultrasonic transducer of the first ultrasonic optical probe to input the ultrasonic wave from the ultrasonic transducer of the first ultrasonic optical probe to the pipe and to supply the ultrasonic wave via the pipe to an optical fiber sensor of the second ultrasonic optical probe; and the light detection module is configured to detect the laser light transmitted through the optical fiber sensor of the second ultrasonic optical probe; wherein the selection module is further configured to select, as the first and second ultrasonic optical probes, a combination of ultrasonic optical probes which are apart from each other at an interval of two second lines in the first direction and at an interval of one first line in the second direction. a power supplying module configured to supply power to the ultrasonic optical probes; a light source configured to generate the laser light and supply the laser light to the ultrasonic optical probes; a light detection module configured to detect the laser light from the ultrasonic optical probes; and a selection module configured to select an ultrasonic optical probe; characterized in that the selection module is configured to select, from the plurality of ultrasonic optical probes attachable to the pipe, a first ultrasonic optical probe to input the ultrasonic wave to the pipe, and a second ultrasonic optical probe to be supplied with the laser light; the power supplying module is configured to supply the power to the ultrasonic transducer of the first ultrasonic optical probe to input the ultrasonic wave from the ultrasonic transducer of the first ultrasonic optical probe to the pipe and to supply the ultrasonic wave via the pipe to an optical fiber sensor of the second ultrasonic optical probe; and the light detection module is configured to detect the laser light transmitted through the optical fiber sensor of the second ultrasonic optical probe; wherein the selection module is further configured to select, as the first and second ultrasonic optical probes, a combination of ultrasonic optical probes which are apart from each other at an interval of two second lines in the first direction and at an interval of one first line in the second direction. <EOS>