A self-position calculating apparatus for calculating a self-position of a vehicle comprising: a light projector configured to be installed in the vehicle and configured to project a patterned light beam (32a, 32b) including multiple spotlights onto a road surface around the vehicle; an image capturing unit configured to be installed in the vehicle, and configured to capture an image of the road surface around the vehicle including an area onto which the patterned light beam (32a, 32b) is projected; an orientation angle calculator configured to calculate an orientation angle of the vehicle relative to the road surface; an orientation change amount calculator configured to calculate amounts of changes in orientation angle of the vehicle relative to the road surface and amount of movement of the vehicle on the road surface based on temporal changes in a plurality of feature points (Te) on the road surface; and a self-position calculator configured to calculate a current position of the vehicle by adding the amount of movement of the vehicle to an initial position of the vehicle and configured to calculate an orientation angle of the vehicle by adding the amount of change in the orientation angle to an initial orientation angle of the vehicle; characterised in that the orientation angle calculator is configured to calculate the orientation angle from a position of the multiple spotlights on the image obtained by the image capturing unit; and the plurality of feature points (Te) are detected from another area within an image capturing range of the image capturing unit, which is different from an area onto which the patterned light beam (32a, 32b) is projected; the apparatus further comprising a detection condition determining section configured to determine a number of the feature points (Te) detected by the orientation change amount calculator; and a patterned light beam controller configured to control whether or not the light projector projects the patterned light beam (32a, 32b), wherein if the detection condition determining section determines that the number of the feature points (Te) is less than a first threshold value, the patterned light beam controller projects the patterned light beam (32a, 32b). a light projector configured to be installed in the vehicle and configured to project a patterned light beam (32a, 32b) including multiple spotlights onto a road surface around the vehicle; an image capturing unit configured to be installed in the vehicle, and configured to capture an image of the road surface around the vehicle including an area onto which the patterned light beam (32a, 32b) is projected; an orientation angle calculator configured to calculate an orientation angle of the vehicle relative to the road surface; an orientation change amount calculator configured to calculate amounts of changes in orientation angle of the vehicle relative to the road surface and amount of movement of the vehicle on the road surface based on temporal changes in a plurality of feature points (Te) on the road surface; and a self-position calculator configured to calculate a current position of the vehicle by adding the amount of movement of the vehicle to an initial position of the vehicle and configured to calculate an orientation angle of the vehicle by adding the amount of change in the orientation angle to an initial orientation angle of the vehicle; characterised in that the orientation angle calculator is configured to calculate the orientation angle from a position of the multiple spotlights on the image obtained by the image capturing unit; and the plurality of feature points (Te) are detected from another area within an image capturing range of the image capturing unit, which is different from an area onto which the patterned light beam (32a, 32b) is projected; the apparatus further comprising a detection condition determining section configured to determine a number of the feature points (Te) detected by the orientation change amount calculator; and a patterned light beam controller configured to control whether or not the light projector projects the patterned light beam (32a, 32b), wherein if the detection condition determining section determines that the number of the feature points (Te) is less than a first threshold value, the patterned light beam controller projects the patterned light beam (32a, 32b).