An object detection apparatus includes: a transmitter transmitting a radio wave with a predetermined intensity at the radio wave transmission end; a receiver receiving the radio wave, which is to be transmitted when the radio wave is transmitted from the transmitter, at the radio wave reception end; a setter setting a transmission scheme of the transmitter to a plurality of different transmission characteristics; a transmission controller controlling the transmitter to transmit the radio wave with the transmission scheme, which is to be set when the setter sets the transmission scheme; and a detector detecting a presence of the object at a position inside the vehicle, based on a detected reception intensity indicating a respective radio wave reception intensity received by the receiver, the object blocking the radio wave transmitted from the transmitter to the receiver at the position inside the vehicle.