Abstract: An object is to provide an inorganic board and a method for manufacturing the same that are suited to achieving high waterproofness. A manufacturing method of the present invention includes first to sixth steps. The first step involves depositing a raw material on a receiving plate B1 to form a first layer L1. The second step involves pressing a first portion Ma and a second portion Mb of a raw material mat M including the first layer L1 toward the receiving plate B1 to compress the first portion Ma and the second portion Mb. The first portion Ma and the second portion Mb are one end portion and the other end portion, respectively, of the raw material mat M in a first direction D1. The third step involves depositing a raw material on the first layer L1 to form a second layer L2. The fourth step involves planarizing an exposed surface of the second layer L2.