PURPOSE: A method for preparing a fertilizer for agricultural crops from medicinal herbs is provided thereby, fertilizer, which is helpful for producing safe agricultural crops, is prepared. CONSTITUTION: The manufacturing method thereof comprises the steps of: (i) extracting medicinal ingredients from medicinal herbs by applying heat thereto or precipitating the medicinal herbs in water to obtain a medicinal liquid; (ii) after putting aerobic microbes or anaerobic microbes, or common anaerobic microbes in the extract or the obtained medicinal liquid of the step (i), fermenting it for certain period of time; and (iii) filtering the fermented solution of the step (ii).