PURPOSE: To obtain a steel sheet that is simultaneously provided with a high strength and an excellent toughness, in the manufacture of a high tension steel containing Nb, Ti, by specifying to combine a steel composition and the manufacturing conditions and obtaining the disconformity precipitation of Nb, Ti.

CONSTITUTION: The steel is used which is in wt.% C: 0.02-0.15, Si: 0.05-0.5, Mn: 1.0-2.0, Al: 0.005-0.05, Nb: 0.01-0.05 and/or Ti: 0.01-0.05, and Fe: the balance. The steel is heated to 1050-1150°C for hot rolling; after hot-rolled at 750-800°C, immediately cooled down to 550-600°C at the cooling velocity of 3-50°C/sec; held for 60-120sec at that temp., and minute ferrite is precipitated. Then, this steel sheet is heated to the temp. at Ac3 -120°C to Ac3 -60°C, held for 60-120sec to precipitate fine deposit, and then after acceleratedly cooled to 400-550°C at the cooling velocity of 3-50°C/sec, it is air cooled.