Provided is an X-ray apparatus and a method of controlling an X-ray apparatus capable of detecting a sign of breakage of a filament. A method of controlling an X-ray apparatus for performing control involving controlling a filament current flowing through a filament of a cathode part to maintain constant a tube current flowing between the cathode part and an anode part with a target, includes: monitoring the current value of at least one of the filament current and the tube current; detecting the mode of change in the current value; determining the presence or absence of a sign of breakage of the filament based on the mode of change in the current value; and issuing a warning based on the determination.