A gas generator supplying a driving fluid to a turbine of a turbopump, the gas generator comprising: an injector configured to inject a fuel and an oxidizer; and a combustor configured to: mix and burn the fuel and the oxidizer injected from the injector; and supply a combustion gas of the fuel and the oxidizer as the driving fluid to the turbine of the turbopump, wherein the injector includes a plurality of injection elements arranged on a same plane, and each of the injection elements includes: one or more fuel injection nozzles for combustion and one or more oxidizer injection nozzles for combustion, which mix and burn each jet of the fuel and the oxidizer at a combustion point in front of the plane in the combustor; and one or more injection nozzles for dilution corresponding to respective fuel injection nozzles, and which are each arranged on a line extending in a direction of each of strong directivities of an impingement jet formed by the mixing of the oxidizer from the oxidizer injection nozzle and the fuel from each of the fuel injection nozzles, each of the one or more injection nozzles configured for mixing a fuel or an oxidizer for dilution injected toward a dilution point located forward further than the combustion point and in front of the plane in the combustor, with a combustion gas generated at the combustion point. an injector configured to inject a fuel and an oxidizer; and a combustor configured to: mix and burn the fuel and the oxidizer injected from the injector; and supply a combustion gas of the fuel and the oxidizer as the driving fluid to the turbine of the turbopump, wherein mix and burn the fuel and the oxidizer injected from the injector; and supply a combustion gas of the fuel and the oxidizer as the driving fluid to the turbine of the turbopump, wherein the injector includes a plurality of injection elements arranged on a same plane, and each of the injection elements includes: one or more fuel injection nozzles for combustion and one or more oxidizer injection nozzles for combustion, which mix and burn each jet of the fuel and the oxidizer at a combustion point in front of the plane in the combustor; and one or more injection nozzles for dilution corresponding to respective fuel injection nozzles, and which are each arranged on a line extending in a direction of each of strong directivities of an impingement jet formed by the mixing of the oxidizer from the oxidizer injection nozzle and the fuel from each of the fuel injection nozzles, each of the one or more injection nozzles configured for mixing a fuel or an oxidizer for dilution injected toward a dilution point located forward further than the combustion point and in front of the plane in the combustor, with a combustion gas generated at the combustion point. one or more fuel injection nozzles for combustion and one or more oxidizer injection nozzles for combustion, which mix and burn each jet of the fuel and the oxidizer at a combustion point in front of the plane in the combustor; and one or more injection nozzles for dilution corresponding to respective fuel injection nozzles, and which are each arranged on a line extending in a direction of each of strong directivities of an impingement jet formed by the mixing of the oxidizer from the oxidizer injection nozzle and the fuel from each of the fuel injection nozzles, each of the one or more injection nozzles configured for mixing a fuel or an oxidizer for dilution injected toward a dilution point located forward further than the combustion point and in front of the plane in the combustor, with a combustion gas generated at the combustion point.