To provide an electric circuit breaker device that can be downsized while maintaining strength. An igniter 20, a bar-shaped projectile 40, a conductor piece 50, and an insulating space 61 are provided inside a resin housing 10. A cylinder 30 is disposed between the bar-shaped projectile 40 and an inner wall surface of the housing 10, and further, a reinforcing frame 70 is disposed in the housing 10 on the outer side. A discharge path for combustion products generated by actuation of the igniter 20 is provided between the insulating space 61 and a second end 12 of the housing.