To provide a portable dust collecting circular saw which smoothes the discharge of chips, enhances dust collecting efficiency in a dust bag and a dust collector, and improves the work efficiency.

Engaging sections of a dust nozzle 6, a saw cover 5 and a nozzle holder 7 are engaged with one another by spherical portions. The saw cover 5 and the nozzle holder 7 are provided with a circumferential groove portion 11. On the rear side a vertical groove portion 12 connected with the circumferential groove portion 11 is provided. The dust nozzle 6 includes three projections 13 so as to fit into the groove 12 having a width, thereby enabling the dust nozzle 6 to incline toward the rear side by rotation.