A detection apparatus and an imaging apparatus are capable of accurately conducting non-destructive observation of a target by using an incoherent electromagnetic wave. The detection apparatus has a generating section, a first coupler section, a delaying section, a second coupler section and a signal processing section. The generating section 101 includes a coherent electromagnetic wave source 102 and a diffusing section 103 for generating a pseudoincoherent electromagnetic wave by changing a propagation state of the coherent electromagnetic wave in accordance with a code pattern. The incoherent electromagnetic wave is split into first and second waves and the first wave is affected by the target of observation while the second wave is delayed by the delaying section. The first and second waves are then coupled to produce a coupled wave having a correlation signal of them and the signal is utilized to acquire information on the inside of the target of observation.