To provide an efficient system for manufacturing an organic fertilizer base material that reduces the manual labor involved in treating livestock manure using Musca domestica larvae. [Solution] Provided is an organic fertilizer production system for producing organic fertilizer from the excreta of livestock by using the larvae of Musca domestica. The organic fertilizer production system is configured as follows: provided is a first cultivation processing housing unit for cultivating larvae hatched from eggs； disposed is a second cultivation processing housing unit that is divided into a plurality of sections below the first cultivation processing housing unit； provided is a drop part that allows the larvae to fall by utilizing the fact that the larvae crawl； an organic fertilizer base is manufactured by letting the larvae fall from the drop part into the next stage of the second cultivation processing housing unit and repeating this process several times, and in each of the cultivation processing housing units, the excreta is enzymatically hydrolyzed within the larvae during the process of rearing the larvae and is subsequently excreted by the larvae； provided are an organic fertilizer base gathering unit that gathers the produced organic fertilizer base material and discharges the same, and a larvae gathering unit that gathers the larvae group that crawled and fell from the final section of the cultivation processing housing unit； and the organic fertilizer base and the larvae group are discharged.
