A system for igniting a combustion chamber of a turboshaft engine, comprising: a plurality of start-up injectors which are suitable for injecting fuel into said chamber during a combustion-initiating phase; a circuit for supplying fuel to said start-up injectors, comprising a first sub-circuit, referred to as the primary start-up circuit, designed to supply fuel to some of said plurality of start-up injectors; a second sub-circuit, referred to as the secondary start-up circuit, designed to supply fuel to the other start-up injectors of said plurality.