Disclosed in the present specification are: an austenitic stainless steel free of surface cracks in a bent portion and having excellent surface roughness; and a manufacturing method thereof. The austenitic stainless steel according to an embodiment of the present invention comprises 0.005-0.03 wt% of C, 0.1-1 wt% of Si, 0.1-2 wt% of Mn, 6-12 wt% of Ni, 16-20 wt% of Cr, 0.01-0.2 wt% of N, and at most 0.25 wt% of Nb, with the balance being Fe and unavoidable impurities, wherein the average grain size (d) value at a center portion in the thickness direction is at most 5 μm, and the martensite area fraction measured in the bent portion after a 180° bending test may be at most 10%.