Distance measuring device and distance measuring method

The distance measuring device includes an irradiation unit that emits slit-shaped irradiation light; a sensor unit that detects the irradiation light irradiated to a distance measurement object; an image processor that generates distance information on the ranging object based on a detection result of the sensor unit; and a controller that calculates a distance measurement object region in accordance with a size of the distance measurement object and sets an irradiation range of the irradiation light of the irradiation unit and a sensing range of the sensor unit to a range corresponding to the object region. 测距装置包括照射单元，其发射狭缝状的照射光；传感器单元，其检测照射到测距对象的所述照射光；图像处理器，其基于所述传感器单元的检测结果生成关于所述测距对象的距离信息；和控制器，其根据所述测距对象的尺寸计算测距对象区域并且将所述照射单元的照射光的照射范围和所述传感器单元的感测范围设定为与所述对象区域相对应的范围。