To provide a rubber weir repair device which is advantageous for securely repairing a broken place while speedily and easily performing repair work.

A guide part 22 and respective moving bodies 14 are inserted into a rubber weir from a broken place of a rubber sheet 202. An operation member 16 is moved into the rubber weir 2, and the moving bodies 14 are placed at spread positions through engagement between a cylindrical cam surface 1612 of the operation member 16 and cylindrical engagement surfaces 1412 of the moving bodies 14. A shaft part 24 of a main body member 12 is inserted into an insertion hole 1802 of a holding plate 18, a nut 20 is threadably engaged with a male screw 2402 of the shaft part 24, and then tightened so as to press the holding plate 18 against a part of the rubber sheet 202 at a periphery of the broken place. Consequently, the overall periphery of the part of the rubber sheet 202 at the periphery of the broken place is held with a holding plate-side projection 30 of the holding plate 18 and moving body-side projections 28 of the moving bodies 14.