Method of producing biodiesel fuel

A method of producing a biodiesel fuel from a raw material oil having an acid value of 20 or less, comprising:

• a step of heating the raw material oil under reduced pressure to distill and remove moisture, odorous substances and free fatty acids;
• a step of causing the raw material oil to come in contact with a hydrophilic adsorbent to adsorb and remove residual free fatty acids and acidic substances;
• a step of subjecting the raw material oil and alcohol to an ester exchange reaction in the presence of an alkali catalyst of at least one type selected from a group including potassium hydroxide, potassium carbonate, and potassium alcoholate;
• a step of separating light liquid components from a reaction product resulting from the ester exchange reaction;
• and
• a step of performing, to the light liquid components, processing of causing the light liquid components to come in contact with a basic substance adsorptive solid adsorbent, processing of removing solid impurities and the like by way of centrifugation, processing of heating the light liquid components under reduced pressure to remove low-boiling substances, and processing of removing solid impurities and the like through a filter.