Electric circuit breaker device

An electric circuit breaker device comprising:

• an igniter provided in a housing;
• a projectile formed in the housing and disposed in an accommodating space extending in one direction, the projectile configured to be projected along the accommodating space by energy received from the igniter,
• a conductor piece provided in the housing and forming a part of an electric circuit, the conductor piece having, as a part of the conductor piece, a cutoff portion configured to be cut off by the projectile moving due to energy received from the igniter, the cutoff portion being disposed crossing the accommodating space;
• and
• an impact absorbing member disposed in an arc-extinguishing region of the accommodating space, the arc-extinguishing region being located on a side opposite to the projectile across the cutoff portion prior to actuation of the igniter and being configured to receive the cutoff portion cut off by the projectile, the impact absorbing member being formed from a resin material that is modified by heat accompanying actuation of the igniter, the impact absorbing member having flexibility, and being configured to absorb impact in a case where the cutoff portion having been cut off collides.