PURPOSE: To provide excellent effect of not development of breakage by repeating for a long period of time by a method wherein one end of an elbow tube, to the other end of which a flexible duct hose is connected, is pivotally connected to a cylindrical discharge tube, which is protrusively provided at the end part of a dust collecting cover.

CONSTITUTION: In the chip discharging device in a running circular saw machine, at the end part of a dust collecting cover 17 surrounding a circular saw 15, a horizontally opened cylindrical discharge tube 18 is protrusively provided. One end of an elbow tube 19, to the other end of which a flexible duct hose 20 is connected, is pivotally connected to the discharge tube 18. Due to the above-mentioned constitution, when the pulling direction of the duct hose 20 changes as the duct collecting cover 17 moves, the elbow tube 19 pivots so as to change its position by the tensile force of the duct hose 20, resulting in developing no bending at the connecting part between the duct hose 20 and the elbow tube 19.