PURPOSE: To continually set beam angle of head lamp at an accurate direction, by detecting the quantities that axis are displaced to a car body, by displaying the quantities and by manually operating this device in response to the display.

CONSTITUTION: A small-sized electric bulb 4 is installed into an electric bulb mounting hole 3 of an approximate central portion of the fan-opening-like space 2 of a case 1 fixed to a car body. An oscillating body 6 is arranged into the space 2 in an oscillation-free shape, and provided with space 7. The space 7 is opened 8 to the rear portion side, the front end side is also opened and colored filters 91, 92, 93 are successively disposed at the front end side along the oscillation direction of the oscillating body 6. The element portions of the oscillating body 6 are supported to the case 1 in oscillation-free shapes. When there is difference between the quantities of before-and-behind axis displaced, the car body tilts to either side of the two of before and behind sides, and the beam direction of the head lamp is manually adjusted in the opposite direction.