The present invention discloses a laser alignment device which has a simple structure, easy operation and economical utility, and which includes a casing, a laser emitting unit that is mounted in the casing and may emit a planar laser beam, a first mounting plane and a second mounting plane connected fixedly to the laser emitting unit, a first and a second electronic obliquity sensing units fixed on the first and the second mounting planes respectively, an automatic adjusting means, a first and a second surfaces both of which may contact with the settling surface of the laser alignment device, said first surface being connected moveably with said laser emitting unit through said automatic adjusting means, and a control circuit connected electrically with said first and second obliquity sensing units and said automatic adjusting means, at least the first one of said first and second obliquity sensing units being a double shaft obliquity sensing unit. Using this configuration, the same laser alignment device may form not only a horizontal planar laser beam but also a vertical planar laser beam, and may sense automatically the deviating degree from the horizontal or vertical for the planar laser beam adjust it automatically, so as to omit the step of adjusting manually and simplify its operation.