A sealing surface processing machine cuts an attachment surface of a seal member in a valve main body. The machine includes a pedestal attached to the valve main body; a main body movably supported on the pedestal; a tool holder configured to hold a tool for processing the attachment surface; a rotating part configured to rotate the tool holder around an axis parallel to a movement direction of a valve body; a first moving part configured to move the tool holder along a first direction along which the valve body moves; a second moving part configured to move the tool holder along a second direction intersecting with the movement direction of the valve body; a first adjustment device configured to adjust a position of the main body in the first direction; and a second adjustment device configured to adjust a position of the main body in the second direction.