To provide a blasting machine having a flow measuring apparatus for accurately measuring the flow of even an electrically non-conductive grinding/polishing/cleaning material as variation in electrostatic capacity.

The capacitance type flow measuring apparatus 70, in which the source electrode 73, the sensing electrode 74 and the guard electrode 75 of a measuring electrode 76 are arranged with angles of 45° to one another over a range of 90° in the circumferential direction of the outer periphery of a cylindrical pipe 72, is positioned on the incident side of a grinding/polishing/ cleaning material projection device, whereby flow of an electrically non-conducting grinding/polishing/cleaning material can be measured with high accuracy.