A camera parameter set calculation apparatus calculates three-dimensional coordinate sets based on a first image obtained by a first camera mounted on a mobile apparatus, a second image obtained by a second camera arranged on or in an object different from the mobile apparatus, a camera parameter set of the first camera, and a camera parameter set of the second camera, determines first pixel coordinate pairs obtained by projecting the three-dimensional coordinate sets onto the first image based on the first camera parameter set and second pixel coordinate pairs obtained by projecting the three-dimensional coordinate sets onto the second image based on the second camera parameter set, calculates an evaluation value based on pixel values at the first pixel coordinate pairs and pixel values at the second pixel coordinate pairs, and updates the camera parameter set of the first camera based on the evaluation value.