Gas generator

A gas generator, comprising:

• an igniter;
• an igniter holding portion having a tubular shape and being configured to hold the igniter in a state of surrounding the igniter;
• a fixing portion made of resin and being configured to fix the igniter to the igniter holding portion;
• and
• a case having a bottomed tubular shape and being configured to accommodate a gas generating agent which combusts by actuation of the igniter, the case being made of resin and including a side wall with a base end side being connected to the fixing portion, and a closing end configured to close a tip end side, wherein
• the closing end includes a fragile part configured to open by a combustion product generated by the gas generating agent,
• a periphery of the fragile part is greater in thickness than the fragile part,
• an annular inclination portion is formed inside the case from a predetermined position of the side wall to the fragile part, and
• a contour of an inner peripheral surface of the case at a boundary between the annular inclination portion and the side wall is a curved line in a longitudinal section of the case.