The present invention relates to a damping apparatus for a moonpool, and more particularly, to a damping apparatus for a moonpool having a simple driving mechanism. The damping apparatus according to the present invention includes one or more damping plates for wholly or partially opening the moonpool of a body of a ship. The damping plate is pivotally hinge-coupled to a sidewall of the moonpool, and one or more transfer units for transferring a drill ship are disposed above the moonpool. Also, a driving wire is connected between each of the transfer units and each of the damping plates to transmit a transferring force of the transfer unit into the damping plate through the driving wire. Thus, the damping plate may be pivoted to wholly or partially open the moonpool.