Abstract: A stainless steel suitable for use with a needle detector, that has a magnetic permeability of 1.005 or less in a magnetic field of 1 kOe, and a magnetization of 550 memu/g or less in a magnetic field of 18 kOe. The steel comprises, in mass %, 0.01 to 0.15% of C, 0.1 to 5% of Si, 1 to 10% of Mn, 8 to 25% of Ni, 14 to 30% of Cr, 0.01 to 0.25% of N, and the remainder Fe and impurities, wherein an Ni equivalent, which is defined as Ni equivalent=Ni+0.6Mn+9.69(C+N)+0.18Cr−0.11Si2, has a value of 19 or more, and may further contain at least one selected from among a) 0.5 to 3% of Cu, b) 0.05 to 0.5% of at least one element selected from Nb, W and V, and c) 0.1 to 2% of Mo.