A distance measuring apparatus includes a light emitter, a receiver, a calculator, a case having a window, and a determiner for determining that dirt is adhered to the window in response to determination that a dirt determination condition is satisfied. The dirt determination condition includes a first condition that a specified light intensity level at a specified value of a time of flight for at least one pixel of a view region in a histogram is larger than or equal to at least one value of an intensity threshold calculated for the at least one pixel of the view region.