The present invention provides a chip discharging device for a machine tool, which is capable of making the entire machine small by minimizing a protruding amount of the chip discharging device toward the backside of the machine, and making an install space thereof small. A column 4 is arranged and fixed on an upper surface of a rear wall portion 2d of a bed 2, the rear wall portion 2d is arranged to deviate upward, rear wall inclined surfaces 2g and 2g′ rising obliquely upward are formed on a bottom portion of the rear wall portion 2d, a storage tank 27 for storing coolant is arranged inside a rectangular frame of the bed 2, the storage tank 27 having a form which extends through a space beneath the rear wall portion 2d to the backside of the machine and further stands up obliquely upward along the rear wall inclined surfaces 2g and 2g′, and a chip conveyor 26 is arranged inside the storage tank 27 for conveying chips to the backside of the machine.