PURPOSE: To manufacture high speed tool steel improved in wear resistance and toughness by subjecting steel powder contg. specified ratios of C, Si, Mn, Cr, W, V and Co to hot isostatic pressing treatment at a specified temp.

CONSTITUTION: The powder of steel having an alloy compsn. contg., by weight, 1.2 to 4.5% C, ≤3.0% Si, ≤3.0% Mn, 3.0 to 10.0% Cr, 15.0 to 60.0% W, 1.0 to 15.0% V and ≤20.0% Co, and the balance substantially Fe is subjected to hot isostatic pressing treatment at a temp. of the melting starting temp. of the carbide included in the steel×0.95 or above. In this way, the wear resistance and toughness of the objective high speed tool steel can be improved by low-cost treatment.