A gas generator, comprising: an ignition device provided at one end of a cylindrical housing and a diffuser portion having a gas discharge port and provided at the other end of the housing, molded articles of a gas generating agent and a molded article of a pressure increasing agent charged into a combustion chamber inside the cylindrical housing, the combustion chamber being a space inside the cylindrical housing excluding the ignition device and the diffuser portion, the molded articles of a gas generating agent being charged, in a charging space remained except for a charging portion for the molded article of a pressure increasing agent inside the combustion chamber, such that the molded articles of a gas generating agent are in contact with the ignition device and a total volume of the molded articles of a gas generating agent is less than a volume of the charging space, the molded article of a pressure increasing agent being charged in contact with the molded articles of a gas generating agent at a position axially distant from the ignition device in the combustion chamber, and the molded article of a pressure increasing agent is positioned apart from the ignition device in an axial direction inside the combustion chamber, a combustion temperature of the molded articles of a gas generating agent being 1000°C to 1700°C, and a combustion temperature of the molded article of a pressure increasing agent being higher than that of the molded articles of a gas generating agent, a charged mass of the molded articles of a gas generating agent being larger than a charged mass of the molded article of a pressure increasing agent, and the molded article of a pressure increasing agent being to burn out before burnout of the molded articles of a gas generating agent at the time of actuation. an ignition device provided at one end of a cylindrical housing and a diffuser portion having a gas discharge port and provided at the other end of the housing, molded articles of a gas generating agent and a molded article of a pressure increasing agent charged into a combustion chamber inside the cylindrical housing, the combustion chamber being a space inside the cylindrical housing excluding the ignition device and the diffuser portion, the molded articles of a gas generating agent being charged, in a charging space remained except for a charging portion for the molded article of a pressure increasing agent inside the combustion chamber, such that the molded articles of a gas generating agent are in contact with the ignition device and a total volume of the molded articles of a gas generating agent is less than a volume of the charging space, the molded article of a pressure increasing agent being charged in contact with the molded articles of a gas generating agent at a position axially distant from the ignition device in the combustion chamber, and the molded article of a pressure increasing agent is positioned apart from the ignition device in an axial direction inside the combustion chamber, a combustion temperature of the molded articles of a gas generating agent being 1000°C to 1700°C, and a combustion temperature of the molded article of a pressure increasing agent being higher than that of the molded articles of a gas generating agent, a charged mass of the molded articles of a gas generating agent being larger than a charged mass of the molded article of a pressure increasing agent, and the molded article of a pressure increasing agent being to burn out before burnout of the molded articles of a gas generating agent at the time of actuation.