To eliminate necessity for temporarily placing and removing of a hatch cover, so that installation work can be performed easily and in a short time, in the case of installing the hatch cover.

An installing method for a hatch cover in a hatch cover mounting ship has a level measuring step using a laser type level measuring device 6 to perform level measurement necessary for installation of the hatch cover, liner thickness determining step calculating a thickness of a height adjusting liner determined to be based on a measuring result of the leveling measuring device 6, liner mounting step mounting a liner of thickness determined by the liner thickness determining step on hatch cover weight receiving parts 2 on a hatch coaming 1, and a hatch cover installing step performing installation of the hatch cover, without previous adjustment of temporarily placing, on the hatch cover weight receiving parts 2 on the hatch coaming 1 with the liner mounted in the liner mounting step.