GAS GENERATOR

A gas generator (1A) includes a lower shell (10) as a housing, an igniter (40) including a squib cup (44) and a plug (43), and a fixing portion (30) formed from a resin molding for fixing the igniter (40) to the lower shell (10). The squib cup (44) includes a contact portion (A) in contact with the plug (43) and a non-contact portion (B) not in contact with the plug (43). The fixing portion (30) includes a cover portion (35) secured to an outer circumferential surface of the squib cup (44), and the cover portion (35) has a lower-side annular cover portion (36) covering a part of the contact portion (A) and an upper-side annular cover portion (37) covering a part of the non-contact portion (B). A thickness t2 of the upper-side annular cover portion (37) is smaller than a thickness t1 of the lower-side annular cover portion (36), and the cover portion (35) is formed in a stepped shape having a substantially two-dimensionally annular step-formed surface (38) orthogonal to an axial direction of the squib cup (44).