There are various types of altars, including stone altars made from naturally table- or board-shaped stone; soil altars made by piling up earth; stonework altars made by laying stones; and altars set up by spreading animal skins or straw mats on the ground.
祭壇の形態は多様で、台や板状の自然石を用いたもの（石壇）、土を盛り上げて作ったもの（土壇）、石を積み上げて作ったもの（石積壇）、地面に獣の皮やコモを敷いたものなどがある。