The present invention relates to an austenitic, lightweight, high-strength steel sheet of which the yield ratio and flexibility are outstanding and to a production method therefor, and more specifically relates to a high-strength steel sheet which can be used in making automobile inner panels or outer panels or else structural parts and to a production method therefor. Provided are: an austenitic, lightweight, high-strength, hot-rolling steel sheet, cold-rolling steel sheet and plated steel sheet of which the yield ratio and flexibility are outstanding, and which comprise, as percentages by weight, from 0.6 to 1.0% of carbon, from 0.1 to 2.5% of silicon, from 10 to 15% of manganese, no more than 0.02% of phosphorus, no more than 0.015% of silicon, from 5 to 8% of aluminium, from 0.01 to 0.20% of titanium, no more than 0.02% of nitrogen, and a balance of iron and unavoidable impurities, wherein the specific weight is no more than 7.4 g/cm3 and the manganese/aluminium ratio is between 2 and 3; and a production method therefor. According to one aspect, the present invention has a lower specific gravity and a higher yield ratio than high strength steels such as AHSS of the prior art and is outstandingly flexible such that it is effective in maintaining the rigidity of structural members and it is outstandingly suitable for press processing and thus it not only allows automobile parts to be made lighter in weight but also allows various parts to be integrated into a single part and hence has the advantage that processing can be simplified.