A distance detection apparatus includes a wave transmitter configured to transmit a transmission wave, a wave receiver configured to receive the transmission wave which is reflected by an object, a storage portion configured to store a transmission signal, a correlation processing portion configured to obtain a correlation value between the transmission signal and a reception signal corresponding to a reception wave, and a detection portion configured to detect a distance to the obstacle in a case where the correlation value indicates that the transmission signal and the reception signal are similar to each other at a level which is equal to or greater than a predetermined level.