There is provided a case-hardening steel in which in inclusion evaluation using an extreme value statistical method, when an estimated area S is 30,000 mm2, an estimated value of the maximum size (√area)S of sulfide-based inclusions present in the estimated area S is 49 μm or less and an estimated value of the maximum size (√area)Ox of oxide-based inclusions present in the estimated area S is 80 μm or less, and the number of sulfide-based inclusions having a length of more than 20 μm and a thickness of more than 2 μm per 1 mm2 is limited to 200 or less,