An apparatus for measuring radio frequency output for a magnetic resonance imaging apparatus includes a plurality of directional couplers, a comparator, a switcher and a converter. The plurality of directional couplers are different in degree of coupling from each other, and attenuate an RF signal which is generated in an RF signal generator and amplified in an RF power amplifier. The comparator compares input-level information of a signal inputted into the RF power amplifier with a threshold value. The switcher switches to any one of the plurality of the directional couplers based on a result of the comparison so as to output an RF signal by the one directional coupler. The converter performs a digital conversion of the RF signal from the one directional coupler so as to output a digital signal.
