Airbag inflator and airbag apparatus

The invention relates to an airbag inflator, comprising a housing (463) having a diffuser shell (461) and a closure shell (462) and forming a single space therein, said diffuser shell (461) having gas discharge ports (477) formed therein, said closure shell (462) including a circular portion (471) having a bent portion (475) defining a center hole (474) formed at a center of said circular portion (471); and an ignition device adapted to generate flames, wherein said ignition device is provided within the single space. Moreover, said ignition device is attached and fixed directly to said bent portion (475).