In a substrate transporter, a carry-in-and-out mechanism transports a substrate placed in a horizontal posture. A notch aligner rotates a substrate in a circumferential direction to change a circumferential position of a notch. The carry-in-and-out mechanism includes four supporters that oppose a lower surface of the peripheral portion of the substrate. In the substrate transporter, a controller controls the notch aligner on the basis of warpage-and-notch-position information and input information that is input about the warped state of the substrate, to determine the circumferential position of the notch of the substrate. Thus, the lower surface of the substrate placed on the transport mechanism comes into contact with the four supporters of the transport mechanism. As a result, it is possible to prevent or suppress the occurrence of rattling or misalignment of the substrate during transport by the transport mechanism, and enables stable transport of the substrate.