A subject information obtaining apparatus according includes: plurality of conversion elements configured to convert an elastic wave from a subject into a plurality of reception signals, a delay and sum unit configured to perform a delay and sum process by using the plurality of reception signals and output a plurality of scanning line signals, a scanning line synthesis unit configured to add the plurality of scanning line signals between adjacent scanning lines and output a plurality of synthesis scanning line signals, and an FDI adaptive processing unit configured to perform a frequency domain interferometry and an adaptive signal processing by using the plurality of synthesis scanning line signals and obtain a power intensity distribution.