The present invention provides a method for producing an inosine derivative represented by the following general formula (1) including the steps of subjecting an inosine derivative of general formula (3) to dithiocarbonylation and carrying out radical reduction of the obtained compound. According to the present invention there can be produced compounds useful as anti-AIDS drugs on industrial scale. wherein R1 may be the same or different and are each benzyl group, benzhydryl group or trityl group, each of which may have a substituent in general formulas (1) and (3).