For feeding seeds contained in a tank main body of a seeds feeding section to a gel coating section by means of suction tips arranged in a seeds transfer section in order to coat them with a gellant, a total of eight through bores are formed along the upper end of the peripheral wall of the tank main body at positions corresponding to the suction tip and arranged at regular intervals so that an annular adaptor having a through bore running through the center thereof is fitted into each of the through bores. The inner peripheral wall of the through bore has a large diameter section located on the outer peripheral side of the peripheral wall for receiving a suction tip and a small diameter section smaller than the large diameter section located on the inner peripheral side of the peripheral wall for allowing seeds to pass therethrough from the tank main body. In a seeds feeding tank of a gel coating apparatus for coating seeds with a gellant and hardening the gellant to produce gel-coated seeds, seeds to be processed can be surely and securely sucked and held by suction tips before they are moved to a downstream processing step of coating seeds with a gellant regardless of the amount of seeds remaining in the seed hopper containing them.