A rubber sheet jointing apparatus is provided with a first holding member for releasably holding a joint end portion of one of two rubber sheets; a second holding member provided movably relative to the first holding member for releasably holding a joint end portion of the other of the two rubber sheets; and an operating member for pressure-contacting the end surfaces of the two rubber sheets respectively held by the first and second holding member by moving the second holding member relative to the first holding member. Mutually facing surfaces of the first and second holding member 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.