A substrate including a channel part having a chamber in which a liquid can be fed stepwise from a chamber to another chamber at the channel part formed in the substrate, depending on the rotational speed of the substrate. A first chamber, a second chamber, a third chamber, and a channel interconnecting them are formed at the channel part formed in the substrate. Furthermore, the width and/or the depth of the first chamber is set smaller than the width and/or the depth of the second chamber. Consequently, the volume of solution subjected to centrifugal force in the first chamber is larger than the volume of solution subjected to centrifugal force in the second chamber.