Abstract: An earth block machine including opposed compaction chambers each receiving a reciprocal compacting member to form solid building blocks by compacting soil. The compacting members are reciprocated by a hydraulically actuated mechanical leverage system connected to the compacting members to produce a very high compaction force while employing a relatively low hydraulic pressure. Each compaction chamber includes a vertically spaced and aligned inlet and outlet provided with a hydraulically powered openable and closable plate to enable inlet of a quantity of soil into the compaction chamber from a supply bin and discharge of the formed earth block from the compaction chamber.