Electric circuit switching device

An electric circuit switching device configured to switch a predetermined first electric circuit from an interrupted state to a conductive state upon actuation, the electric circuit switching device comprising:

• a housing;
• an igniter provided in the housing and configured to release a combustion gas upon actuation;
• a tubular space formed in the housing and extending in one direction;
• a projectile having conductivity and positioned at a predetermined first position in the tubular space in an initial state before actuation of the igniter;
• a piston fixed to the projectile and disposed in the tubular space interposedly between the igniter and the projectile, and configured to be projected in a predetermined projecting direction along the tubular space by energy of the combustion gas;
• and
• a pair of first conductor pieces provided inserted, in a spaced apart state, into the tubular space at a position closer to the projecting direction side than the first position, and forming part of the first electric circuit in cooperation with each other, wherein
• the projectile projected integrally with the piston upon actuation of the igniter comes into contact with each of the pair of first conductor pieces, switching the first electric circuit from the interrupted state to the conductive state.