A micro-machined or micro-engraved safety and arming device for a projectile pyrotechnic train, said device comprising a substrate onto which a shutter is positioned to ensure the blocking of a channel, said shutter being mobile in translation on said substrate, said shutter being held immobile in the safety position by at least one acceleration lock that is released further to the application of the axial acceleration imparted to said projectile during firing, wherein said acceleration lock is constituted by at least one breakable tongue linking said shutter to said substrate, said tongue being oriented and dimensioned such that the axial inertial stresses developed during firing and exerted on said shutter cause said tongue to break.