An apparatus for cleaning inner surfaces of molds such as ingot molds, which comprises a swivel ring rotatably mounted on travelling means, means for swivelling said ring, guiding means mounted on said swivel ring, and a cleaner assembly elevatably supported in said guiding means. The cleaner assembly comprises a cleaner shaft having a plurality of cleaning members such as link chains, which is adapted to be rotated and oscillated during operation. The apparatus makes it possible to clean the inner surfaces of bottle-shaped molds with high efficiency, as well as those of normal molds. The apparatus can be controlled remotely through television.