A distance-measuring apparatus (2000) generates transmission light by generating a distance measurement signal, and subjecting an optical carrier wave to quadrature modulation on the basis of the generated distance measurement signal. The distance-measuring apparatus (2001) outputs transmission light, and receives reflected light generated by reflecting the transmission light on an object (10) to be measured. The distance-measuring apparatus (2000) compares the received reflected light with reference light to compute a distance from the distance-measuring apparatus (2000) to the object (10) to be measured.