A rubber sheet jointing apparatus is provided with first holding means for releasably holding a joint end portion of one of two rubber sheets, second holding means provided movably relative to the first holding means for releasably holding a joint end portion of the other of the two rubber sheets, and operating means for pressure-contacting the end surfaces of the two rubber sheets respectively held by the first and second holding means by moving the second holding means relative to the first holding means. Mutually facing surfaces of the first and second holding means are respectively provided with holder portions which are formed as rugged portions each taking a comb tooth shape and which are able to partly overlap to mesh with each other.