Abstract: A distance measuring device is applicable to a sweeping robot and includes a signal source disposed near a front end edge of a bottom surface of the sweeping robot and configured to transmit a cone-shaped detection signal at a preset angle; a first signal receiver disposed at a first position near the signal source and configured to receive a reflected signal of the cone-shaped detection signal reflected by the ground, wherein the first position is a corresponding position when a projected area of the cone-shaped detection signal on the ground is maximum; and a second signal receiver disposed at a second position near the first signal receiver and configured to receive a reflected signal of the cone-shaped detection signal reflected by a cliff surface, wherein the second position is a corresponding position when a projected area of the cone-shaped detection signal on the cliff surface is maximum.