A distance measuring system and a controlling method of the system can reduce power consumption of a distance measuring apparatus acquiring an image including distance information. For example, the distance measuring system includes a distance measuring apparatus acquiring distance information concerning an image capturing target, a calculating unit estimating an estrangement period in which the image capturing target cannot be recognized in an image, based on the distance information, and a controlling unit setting the distance measuring apparatus to a power saving mode of controlling an acquiring frequency of the image according to the estrangement period when the estrangement period is a first threshold value or more, and setting the distance measuring apparatus to a normal mode of controlling the acquiring frequency of the image independently from the estrangement period when the estrangement period is less than the first threshold value.