A cylinder member of an automatic transmission that includes an outer peripheral introducing portion having a shape that is able to be formed by ironing without forming and trimming of a flange portion which was conventionally required for forming an outer peripheral introducing portion. Therefore, steps required for forming the flange portion are omitted, and the number of steps for manufacturing the cylinder member is reduced. Without using a large-scale press machine such as a progressive press and a transfer press, the cylinder member is manufactured by a smaller-sized press machine, thereby reducing equipment investment required for manufacturing the cylinder member.