To provide a blade attachment-detachment-system for an easily detachable, long-life saber saw.

The system comprises: a plunger 20, which is equipped with a slit 20d to insert a blade 27 and a through-hole 20e penetrating orthogonally to the axial direction of the slit to reach at least to the slit, and is able to reciprocate along the axial direction; a locking pin 30 which is pressed and locked to a slit wall; and a first blade holder 28, which is set up movable along the axial direction of the plunger on its tip. The blade is attachable or detachable by applying or lifting press on the locking pin at an advanced or a retreated state of the blade holder.