Patent ID: 8100041

Claim:
A miter saw comprising: a base that supports a workpiece thereon; a movable portion supported to the base and movable relative to the base; a circular saw unit that rotatably supports a circular saw blade, the circular saw blade being rotatably driven only by a main power source; a support section provided to the movable portion and pivotally movably supporting the circular saw unit at a position above the movable portion; a moving amount detection unit that electrically detects a moving amount of the movable portion relative to the base; a computing unit that computes a moving quantity of the movable portion based on the moving amount detected by the detection unit; a storage unit that stores the moving quantity computed by the computing unit; and a battery unit that supplies an electric power to the moving amount detection unit, the computing unit, and the storage unit, wherein the main power source is supplied as the power source to the moving amount detection unit, the computing unit, the storage unit and the circular saw unit when the main power source is connected thereto, and the battery unit is supplied as the power source to the moving amount detection unit, the computing unit and the storage unit, but is not supplied to the circular saw unit when the main power source is disconnected therefrom, so that the moving amount detection unit, the computing unit and the storage unit will continue to be supplied with power from the battery power source when the main power source is turned off, and, further comprising a digital display that displays the moving amount computed in the computing unit or stored in the storage unit, the digital display being turned off if the electrical power supply is performed exclusively from the battery.