A spring retainer is made from an iron-based material to improve the strength and abrasion resistance of the spring retainer and reduce the thickness and weight thereof. The spring retainer includes a retainer body having a tapered support hole to be supported with a valve stem and a flange-like spring seat circumferentially formed on a periphery at a first side of the retainer body to receive and support a valve spring. The retainer body and spring seat are integrally formed from resilient steel with grain flows continuously formed from the retainer body to the spring seat.