A steel consisting of: C in a content of from 0.65% to 1.30%; Si in a content of from 0.05% to 1.00%; Mn in a content of from 0.1% to 2.00%; P in a content of from greater than 0% to 0.050%; S in a content of from greater than 0% to 0.050%; Cr in a content of from 0.15% to 2.00%; Al in a content of from 0.010% to 0.100%; N in a content of from greater than 0% to 0.025%; Ti in a content of from greater than 0% to 0.015%; and O in a content of from greater than 0% to 0.0025%, optionally further consisting of at least one element selected from the group consisting of: Cu in a content of from greater than 0% to 0.25%; Ni in a content of from greater than 0% to 0.25%; and Mo in a content of from greater than 0% to 0.25%, optionally further consisting of at least one element selected from the group consisting of: Nb in a content of from greater than 0% to 0.5%; V in a content of from greater than 0% to 0.5%; and B in a content of from greater than 0% to 0.005%, optionally further consisting of at least one element selected from the group consisting of: Ca in a content of from greater than 0% to 0.05%; REM or REMs in a content of from greater than 0% to 0.05%; Mg in a content of from greater than 0% to 0.02%; Li in a content of from greater than 0% to 0.02%; and Zr in a content of from greater than 0% to 0.2%, optionally further consisting of at least one element selected from the group consisting of: Pb in a content of from greater than 0% to 0.5%; Bi in a content of from greater than 0% to 0.5%; and Te in a content of from greater than 0% to 0.1%, in mass percent, with the balance consisting of iron and inevitable impurities, wherein: Al-containing nitrogen compound particles dispersed in the steel have an average equivalent circle diameter of from 25 to 200 nm; and Al-containing nitrogen compound particles each having an equivalent circle diameter of from 25 to 200 nm are present in a number density of from 1.1 to 6.0 per square micrometer. C in a content of from 0.65% to 1.30%; Si in a content of from 0.05% to 1.00%; Mn in a content of from 0.1% to 2.00%; P in a content of from greater than 0% to 0.050%; S in a content of from greater than 0% to 0.050%; Cr in a content of from 0.15% to 2.00%; Al in a content of from 0.010% to 0.100%; N in a content of from greater than 0% to 0.025%; Ti in a content of from greater than 0% to 0.015%; and O in a content of from greater than 0% to 0.0025%, Cu in a content of from greater than 0% to 0.25%; Ni in a content of from greater than 0% to 0.25%; and Mo in a content of from greater than 0% to 0.25%, Nb in a content of from greater than 0% to 0.5%; V in a content of from greater than 0% to 0.5%; and B in a content of from greater than 0% to 0.005%, Ca in a content of from greater than 0% to 0.05%; REM or REMs in a content of from greater than 0% to 0.05%; Mg in a content of from greater than 0% to 0.02%; Li in a content of from greater than 0% to 0.02%; and Zr in a content of from greater than 0% to 0.2%, Pb in a content of from greater than 0% to 0.5%; Bi in a content of from greater than 0% to 0.5%; and Te in a content of from greater than 0% to 0.1%, Al-containing nitrogen compound particles dispersed in the steel have an average equivalent circle diameter of from 25 to 200 nm; and Al-containing nitrogen compound particles each having an equivalent circle diameter of from 25 to 200 nm are present in a number density of from 1.1 to 6.0 per square micrometer.