A vehicle headlamp apparatus comprising: a low beam lamp unit which forms a low beam distribution pattern having a cutoff line (CL1, CL2, CL3) along an upper edge thereof; and an additional lamp unit (28, 30) which forms an additional light distribution pattern including an area above the cutoff line (CL1, CL2, CL3) of the low beam distribution pattern, wherein the additional lamp unit (28, 30) is configured such that a luminous intensity of at least a portion of the additional light distribution pattern increases toward a horizontal line from above, wherein the additional lamp unit (28, 20) comprises a light source (56N1-56N8), a light source image forming member (60, 80) which forms a light source image with a light emitted from the light source (56N1-56N8), and a projection lens (52, 72) through which the light source image is projected to form the additional light distribution pattern, wherein the light source image forming member (60, 80) comprises a front surface (60e, 80e) facing the projection lens (52, 72), and light guide paths (60a-60d, 80a-80d) arranged side by side in a left-right direction, each of the light guide paths (60a-60d, 80a-80d) having an opening at the front surface (60e, 80e), wherein internal faces of each of the light guide paths (60a-60d, 80a-80d) are configured as reflecting faces for reflecting the light emitted from the light source (56N1-56N8) toward the projection lens (52, 72), wherein each of the light guide paths is configured such that an angle formed by the upper internal face and the optical axis of the projection lens (52, 72) is within a range of greater than -θ1 but smaller than θ1, wherein, assuming that the upward inclination from the optical axis of the projection lens (52, 72) is the positive side, -θ1 is the angle formed by the lower internal face and the optical axis of the projection lens (52, 72), whereby luminous intensity of the light reflected toward the projection lens (52, 72) so as to form a lower part of the additional light distribution pattern is higher than a luminous intensity of the light reflected toward the projection lens (52, 72) so as to form an upper part of the additional light distribution pattern, characterized in that some of the light guide paths (60a-60d, 80a-80d) are formed such that a lateral width of the light guide path (60a-60c) is rearwardly widened from the opening at the front surface and that a lateral width of one light guide path is maintained the same in the rearward direction from the opening at the front surface. a low beam lamp unit which forms a low beam distribution pattern having a cutoff line (CL1, CL2, CL3) along an upper edge thereof; and an additional lamp unit (28, 30) which forms an additional light distribution pattern including an area above the cutoff line (CL1, CL2, CL3) of the low beam distribution pattern, wherein the additional lamp unit (28, 30) is configured such that a luminous intensity of at least a portion of the additional light distribution pattern increases toward a horizontal line from above, wherein the additional lamp unit (28, 20) comprises a light source (56N1-56N8), a light source image forming member (60, 80) which forms a light source image with a light emitted from the light source (56N1-56N8), and a projection lens (52, 72) through which the light source image is projected to form the additional light distribution pattern, wherein the light source image forming member (60, 80) comprises a front surface (60e, 80e) facing the projection lens (52, 72), and light guide paths (60a-60d, 80a-80d) arranged side by side in a left-right direction, each of the light guide paths (60a-60d, 80a-80d) having an opening at the front surface (60e, 80e), wherein internal faces of each of the light guide paths (60a-60d, 80a-80d) are configured as reflecting faces for reflecting the light emitted from the light source (56N1-56N8) toward the projection lens (52, 72), wherein each of the light guide paths is configured such that an angle formed by the upper internal face and the optical axis of the projection lens (52, 72) is within a range of greater than -θ1 but smaller than θ1, wherein, assuming that the upward inclination from the optical axis of the projection lens (52, 72) is the positive side, -θ1 is the angle formed by the lower internal face and the optical axis of the projection lens (52, 72), whereby luminous intensity of the light reflected toward the projection lens (52, 72) so as to form a lower part of the additional light distribution pattern is higher than a luminous intensity of the light reflected toward the projection lens (52, 72) so as to form an upper part of the additional light distribution pattern, characterized in that some of the light guide paths (60a-60d, 80a-80d) are formed such that a lateral width of the light guide path (60a-60c) is rearwardly widened from the opening at the front surface and that a lateral width of one light guide path is maintained the same in the rearward direction from the opening at the front surface.