Abstract: The present invention provides an improved rupture disk apparatus and manufacturing method. The apparatus includes a rupture disk having at least one area of weakness formed by the displacement of material through a partial shearing motion. The weakened area is capable of withstanding pressure cycling because the rupture disk flange acts to support the weakened area during use. The apparatus further includes a safety member adjacent to the rupture disk on the outlet side to ensure opening, the safety member having at least one rupture-initiating, stress-concentrating point positioned to contact the rupture disk weakened area.