A process for producing a camshaft with cams include the steps of forming a surface hardened layer in each of the cams by a remelting chilling treatment using high density energy (e.g., a TIG arc), characterized in that after the remelting chilling treatment, the camshaft is cooled by passing a cooling medium through a through hole formed longitudinally in the camshaft. As a result of the cooling, the neighboring untreated cam has a temperature of up to 250.degree. C. Elongation of the camshaft due to thermal expansion is so small that no melt-down end portion defects appear.