A self-location calculating device comprising: a light projector configured to project a patterned light onto a road surface around a vehicle; an image capturing unit installed in the vehicle, and configured to capture and obtain an image of the road surface around the vehicle including an area onto which the patterned light is projected; and an attitude angle calculation unit configured to calculate an attitude angle of the vehicle relative to the road surface from a position of the patterned light on the image obtained by the image capturing unit; a self-location calculation unit configured to calculate a current position and a current attitude angle of the vehicle; characterized by an attitude change amount calculation unit configured to calculate an amount of change in an attitude of the vehicle based on temporal changes in a plurality of feature points on the road surface on the image obtained by the image capturing unit; the self-location calculation unit being configured to calculate the current position and the current attitude angle of the vehicle by adding the amount of change in the attitude to an initial position and the attitude angle of the vehicle; and a running condition determination unit configured to detect a running condition of the vehicle, and to determine whether or not the vehicle is in a stable running state, wherein when the running condition determination unit determines that the vehicle is in the stable running state, the self-location calculation unit calculates the current position and the current attitude angle of the vehicle by adding the amount of change in the attitude to a position of the vehicle which is in the stable running state and a predetermined initial attitude angle of the vehicle which is in the stable running state. a light projector configured to project a patterned light onto a road surface around a vehicle; an image capturing unit installed in the vehicle, and configured to capture and obtain an image of the road surface around the vehicle including an area onto which the patterned light is projected; and an attitude angle calculation unit configured to calculate an attitude angle of the vehicle relative to the road surface from a position of the patterned light on the image obtained by the image capturing unit; a self-location calculation unit configured to calculate a current position and a current attitude angle of the vehicle; characterized by an attitude change amount calculation unit configured to calculate an amount of change in an attitude of the vehicle based on temporal changes in a plurality of feature points on the road surface on the image obtained by the image capturing unit; the self-location calculation unit being configured to calculate the current position and the current attitude angle of the vehicle by adding the amount of change in the attitude to an initial position and the attitude angle of the vehicle; and a running condition determination unit configured to detect a running condition of the vehicle, and to determine whether or not the vehicle is in a stable running state, wherein when the running condition determination unit determines that the vehicle is in the stable running state, the self-location calculation unit calculates the current position and the current attitude angle of the vehicle by adding the amount of change in the attitude to a position of the vehicle which is in the stable running state and a predetermined initial attitude angle of the vehicle which is in the stable running state.