An object detection apparatus is applied to a movable body including an object detection sensor which transmits a search wave and receives a reflected wave of the search wave as detection information of an object, and detects the object present around the movable body based on the detection information. The apparatus includes a frequency detection section which detects an occurrence frequency of a disturbance signal at the same time within a predetermined transmission time period determined with reference to a transmission period of the search wave, and a disturbance determination section which determines presence or absence of occurrence of disturbance based on the occurrence frequency detected by the frequency detection section.