1. A specific absorption rate measuring apparatus, comprising: a probe configured to measure, in a two-dimensional plane for a two-dimensional distribution of points, an amplitude and a phase of an electric or magnetic field generated in a phantom having electrical properties similar to those of human body tissues; a field estimation unit configured to estimate a three-dimensional electric or magnetic field distribution to be produced from a wave source defined by the measured two-dimensional distribution at a specific measuring point, based on a measurement result of the probe at the specific measuring point; and a specific absorption rate estimation unit configured to estimate a three-dimensional distribution of a specific absorption rate for points other than the specific measuring point from the estimated three-dimensional electric or magnetic field distribution.