A piercing die, a holding body, and a piercing punch are used to form a pressed component having a plate-shaped base portion and a tubular boss portion extending from the base portion. The piercing die has a receiving portion, an outer shape-forming portion, and a die-side cutting edge. The piercing punch has an inner shape-forming portion, a punch-side cutting edge, and a straight portion. In a process of forming a pressed component, the piercing punch is pressed against a preform which is formed from a blank and which has a preliminary boss portion so as to cause part of the preliminary boss portion to flow toward the outer shape-forming portion, and so as to then cut off another part of the preliminary boss portion to form a boss portion.