The present invention has as its technical problem to prevent cracking when producing a steel sheet by ferritic stainless steel sheet and provide a ferritic stainless steel sheet excellent in toughness and a part using the same. To solve this technical problem, the present invention provides steel comprised of, by mass %, C: 0.001 to 0.030%, Si: 0.01 to 1.00%, Mn: 0.01 to 1.00%, P: 0.010 to 0.050%, S: 0.0002 to 0.0100%, Cr: 10.0 to 20.0%, N: 0.001 to 0.030%, Nb: 0.10 to 0.40%, B: 0.0002 to 0.0030%, Al: 0.005 to 0.100%, and a balance of Fe and unavoidable impurities in which the amount of solute Nb being less than or equal to a smaller value of 0.20 and (Nb content-0.08) mass %.