Toha Heavy Industries (originally Toua-juukou (東亜重工?)) is a massive edifice or possibly vehicle separate from the megastructure. Toha Heavy Industries was mentioned as the benevolent organization in Biomega as well as a mecha manufacturer in Knights of Sidonia. It is inhabited by humans known only as the Planters, and is the origin of the splinter group, the Electrofishers. It is controlled by a Central AI, and has a collective of thirteen other AIs; one controlling each cave. The Collective AI was created in an effort to prevent insanity, however, in the end it didn't work out. The Central AI shows increasingly irrational behavior with its use of teleportation technology, and its gravity furnace. The AI isolated itself from the outside using a treaty from the Governing Agency because of the seriousness of the Silicon Creature's disease, and excommunicated those who did. Toha Heavy Industries is crucial because the Planters may be netgene carriers.

Toha Heavy Industries had a treaty with Netsphere until it was broken by the Central AI. It prevented the Safeguard and the Governing Agency from operating withing Toha Heavy Industries. This is why Cibo could use Sanakan's body without problems after entering it.