A method of introducing solution into the wells of a multiwell plate comprised of a substrate having multiple wells on at least one principal surface thereof. The wells are imparted dimensions, shapes, and surface configurations such that when said multiwell plate is positioned in stationary fashion with the openings of said wells facing upward, said solution does not enter said wells even when the openings of said wells are covered by said solution, and the solution is positioned on said principal surface of said multiwell plate having wells and a centrifugal force oriented from the well opening toward the bottom is applied to introduce said solution into said wells. Provided is a method for conveniently filling vessels (wells) with a solution such as a reaction solution, even when the vessels (wells) number in excess of 1,000, and even when the dimension, shape, and surface configuration of the vessels (wells) do not permit fluid to flow into the vessels (wells).