An optical module of a head lamp including a first light source unit, a first reflection unit configured to concentrate, at a first focal point, light radiated from the first light source unit, a first shield unit positioned in the first focal point, second light source units, a second reflection unit configured to concentrate, at second focal points, light radiated from the second light source units, a second shield unit positioned in the second focal points, a hot zone lens unit positioned on the output side of the first shield unit and configured to form a light distribution pattern parallel to horizontal and vertical directions, by transmitting light radiated from the first shield unit, and a wide zone lens unit positioned on the output side of the second shield unit and configured to form a light distribution pattern spread in the horizontal direction, by transmitting light radiated from the second shield unit.