A magnetic field measuring method in a magnetic resonance imaging (MRI) apparatus includes applying a radio frequency (RF) pulse to an object, acquiring first and second echo signals from a first readout gradient according to test gradients having different intensities, acquiring third and fourth echo signals from a second readout gradient according to the test gradients having different intensities, and determining a characteristic value of an eddy field based on an echo time (TE) of at least one of the first through the fourth echo signals.