To provide a portable dust collecting circular saw wherein even when a protruded distance of a saw blade from a bottom surface of a base is decreased and a clearance between a bottom surface of a saw cover of a front part in a cutting direction and an upper surface of the base is enlarged, a lower end of a sliding cover covers a blade tip part to prevent scattering of chips to an operator and an operation property of the sliding cover is improved.

In the portable dust collecting circular saw having a base 4 capable of adjusting the protruded distance 5 of the saw blade by pivoting to a main body 10; the saw cover 2 having a shape of forming a clearance between the front lower end of the cutting direction and the upper surface of the base 4 by covering almost an upper part positioning above the base 4 of the saw blade 5 to be provided to the main body 10; and the sliding cover 1 capable of blocking the clearance by being provided movably to front in a cutting direction of the saw cover 2, a bottom surface of the sliding cover 1 has a shape of inclining in a direction of separating from the upper surface of the base 4 over to front in the cutting direction from rear in the cutting direction.