A laser scanner, comprising a mirror rotatably provided, a driving unit for rotating the mirror, a distance measuring unit for projecting a distance measuring light for scanning to a measurement range via the mirror and for obtaining a position data by receiving the reflected distance measuring light via the mirror, a measuring direction observing means for indicating a projecting direction of the distance measuring light, and an operation unit for setting the measurement range by designating at least two measuring directions based on the result of observation of the measuring direction obtained by the measuring direction observing means.