The present invention provides a steel for machine and structural use which is capable of maintaining mechanical characteristics such as strength by reducing a S content as well as of exhibiting excellent machinability (particularly tool life) in intermittent cutting (such as hobbing) with the high speed tool, and a method useful for producing the steel for machine and structural use. The steel for machine and structural use according to the invention secures 0.002% or more of solute N in the steel and has a chemical composition which is appropriately adjusted and satisfies a relationship of the following expression (1): (0.1×[Cr]+[Al])/[O]≧150 . . . (1), in which [Cr], [Al], and [0] represent a Cr content (mass %), an Al content (mass %), and an O content (mass %), respectively.