Abstract: A method of producing earthworm castings by feeding earthworms with feed prepared by mixing solid fuel ash with shells, crab shells and yellow earth and to an earthworm bed for producing earthworm castings, comprises the steps of: grinding solid fuel ash; washing shells and crab shells to remove salt, and then removing 80% or more of water therefrom; grinding the washed shells and crab shells; mixing 60-70 wt % of yellow earth, 20-30 wt % of the solid fuel ash and 10-20 wt % of the ground shells and crab shells; fermenting and maturing the mixture; and feeding the matured mixture to earthworms to allow the earthworms to produce earthworm castings. The earthworm bed (50) comprises: a feeding unit (52) through which feed prepared by mixing solid fuel ash with shells, crab shells and yellow earth is fed; a breeding chamber (51) in which earthworms are bred to produce earthworm castings; and a discharge unit (53) through which the earthworm castings produced in the breeding chamber (51) are discharged.