Abstract: A portable chain saw includes a flexible brake band for stopping the cutter chain. A sensing arm is pivotally mounted on the chain saw housing, with the brake band being connected to this sensing arm. The sensing arm is arranged to be engaged by an arm or hand of an operator so as to be swung forwardly in a brake-tightening manner. The sensing arm is continuously biased forwardly to a braking position by a coil compression spring. A latch normally holds the sensing arm in a rest position. The latch comprises a metallic strip one end of which is fixedly secured to the housing. The other end of the strip has a bent configuration defining a notch for receiving a curved projection of the sensing arm to retain the latter. The strip extends forwardly from the housing in overlying position above the spring and projection.