The invention discloses a clearance adjusting apparatus, a clearance adjusting method and a conveyance device. The clearance adjusting apparatus is used for adjusting a clearance between two opposite rollers and comprises: a driver for driving the roller to move up and down, at least one of the rollers being movable relative to the other; and a controller that stores a predetermined clearance scope being connected with the driver for controlling the driver to drive the movable roller to move up and down, so that the clearance between the two rollers falls into the predetermined clearance scope.