A portable electric circular saw with a tiltable base plate is disclosed herein. The circular saw comprises a housing for accommodating an electric motor, a circular saw blade operatively connected to the motor to be driven thereby, a safety guard connected to the housing for enclosing the portion of the saw blade, the base plate upon which the above parts are mounted and which is adapted to engage upon the surface of a workpiece to be sawed, and a bracket for attaching the base plate to the housing. One end portion of the bracket is secured to the housing and the opposite end thereof is pivotally connected to the base plate such that the base plate can pivot about an axis within the plane of the saw blade for adjustment of the angle of the cut. The base plate joins the bracket by fastening means at the portion intermediate the ends of the bracket after the base plate is set at a desired angle with respect to the saw blade. Thus the base plate is linked through the bracket to the housing itself and is not required to be connected to the safety guard, which eliminates the necessity of giving a greater strength to the safety guard enough to be securely connected at its front end to the base plate. Accordingly, the safety guard can be made of lightweight material free from the strength requirement such that the overall weight of the circular saw can be reduced so as to be easily manipulated.