Provided is a battery-powered working machine including a protective bracket (50) which is able to be secured to a casing (2) while being in engagement with a battery pack (4), which is capable of preventing theft of the battery pack (4), and which separates a casing-side connection terminal (21) from a battery-side connection terminal (43) at a distance to keep the casing-side and battery-side connection terminals (21) and (43) out of contact with each other.