A direct injection fuel injection valve includes a valve casing housing therein a valve member and fitted into an engine main body of an internal combustion engine. The casing includes: a tubular case member; and a valve seat member joined to one end part thereof and having a valve seat and a fuel injection hole. The valve member can be in contact with and detached from the valve seat. The injection hole is opened and closed by cooperation between the valve seat and the valve member. At least part of the valve seat member is exposed to a combustion chamber of the engine main body. Fuel can be injected into the combustion chamber via the injection hole. The valve seat member is formed from a martensitic stainless steel having a PI value of at least 19, containing at least N, and having a C content of no greater than 0.3%.