Abstract: A underwater mobile type inspection system is disclosed wherein said system comprises a multi-articulated manipulator with a probe attached at its tip end thereof. A pivot base supports the proximal end of the manipulator for free rotation and is provided with a propulsion device. An anchoring base is attached to the bottom of said pivot base via a pivot driving mechanism. An adhesion device and a mobile vehicle device are provided, both of which are mounted on the outer periphery of said anchoring base. The inspection system may be applicable to a defect finding operation, other inspecting procedures, cleaning and recovery operations of foreign materials in large-sized vessels, such as nuclear reactor pressure vessels, water pools and storage tanks etc.