A laser radar device comprising: a scattered light measurement instrument to measure a temporal change in scattered light intensity of scattered light acquired through scattering of a light wave while propagating; a distance measurement instrument to perform a distance measurement on surroundings by using reflected light of a light wave; a measurable distance calculator to calculate an amount of attenuation at a time of propagation of the light wave from the temporal change in the scattered light intensity which is measured by said scattered light measurement instrument, and calculate a measurable distance in said distance measurement instrument from said amount of attenuation, wherein the measurable distance calculator has a function of, by using two threshold voltages V 1 and V 2 which are set in advance, measuring the times t 1 and t 2 when a scattered light intensity signal has values less than the threshold voltages V 1 and V 2, respectively, to calculate an attenuation coefficient showing the amount of attenuation; a target detector to calculate three dimensional data from distances of surrounding points which are measured by said distance measurement instrument, to detect a target from said three dimensional data; a moving route calculator to calculate a moving route of a moving object by using the measurable distance calculated by said measurable distance calculator; a position direction recognizer to measure an angular speed of said moving object and an acceleration of said moving object to recognize a position and a direction of said moving object; and a movement controller to move said moving object according to the moving route calculated by said moving route calculator. a scattered light measurement instrument to measure a temporal change in scattered light intensity of scattered light acquired through scattering of a light wave while propagating; a distance measurement instrument to perform a distance measurement on surroundings by using reflected light of a light wave; a measurable distance calculator to calculate an amount of attenuation at a time of propagation of the light wave from the temporal change in the scattered light intensity which is measured by said scattered light measurement instrument, and calculate a measurable distance in said distance measurement instrument from said amount of attenuation, wherein the measurable distance calculator has a function of, by using two threshold voltages V 1 and V 2 which are set in advance, measuring the times t 1 and t 2 when a scattered light intensity signal has values less than the threshold voltages V 1 and V 2, respectively, to calculate an attenuation coefficient showing the amount of attenuation; a target detector to calculate three dimensional data from distances of surrounding points which are measured by said distance measurement instrument, to detect a target from said three dimensional data; a moving route calculator to calculate a moving route of a moving object by using the measurable distance calculated by said measurable distance calculator; a position direction recognizer to measure an angular speed of said moving object and an acceleration of said moving object to recognize a position and a direction of said moving object; and a movement controller to move said moving object according to the moving route calculated by said moving route calculator.