A headlamp control apparatus for controlling a headlamp of a host vehicle that includes a plurality of semiconductor light sources (34R/L-1 to 34R/L-20), and the headlamp control apparatus being capable of altering brightness partly in an irradiated region according to on-off state of plurality of operation modes, wherein an operation mode individually corresponds to one of the various functions of the headlamp, such as for example the glare restraint function or the pedestrian spotting function, the headlamp control apparatus comprising: a mode information reception portion (108, 116) configured to receive, via a predetermine communication line, the mode information wherein the mode information indicates an on/off state of each of the operation modes and specifies, at least for one of said operation mode, sectional resultant regions, in which brightness needs to be altered if said at least one operation mode is on, wherein the sectional resultant regions are the divided regions of a resultant irradiated region that is a combination of the irradiated region of the left and right headlamps, the mode information includes a region ID code for each of the plurality of sectional resultant regions (1 to 23); a correspondence relation retention portion (114, 122) that retains the region ID code and a light source ID code that identifies one of the plurality of semiconductor light sources that illuminates the sectional resultant region identified by the region ID code, with the region ID code and the light source ID associated with each other; a state determination portion (110, 118) configured to refer to the correspondence relation retention portion (114, 112) to determine a state of each of the plurality of semiconductor light sources (34R/L-1 to 34R/L-20) based on which sectional resultant regions is specified by the mode information received by the mode information reception portion (108, 116), if the mode information received indicates that one of the at least one operation mode is on, wherein the state determination portion (110,118) is further configured to refer to the correspondence relation retention portion (114, 122) to determine at least one of the semiconductor light sources that is identified by the light source ID code corresponding to the region ID code included in the mode information, as the semiconductor light source whose luminance needs to be altered; and a light source control portion (112, 120) configured to control the plurality of semiconductor light sources (34R/L-1 to 34R/L-20) so as to cause each of the plurality of semiconductor light sources (34R/L-1 to 34R/L-20) to be brought into the state determined by the state determination portion (110, 118), a mode information reception portion (108, 116) configured to receive, via a predetermine communication line, the mode information wherein the mode information indicates an on/off state of each of the operation modes and specifies, at least for one of said operation mode, sectional resultant regions, in which brightness needs to be altered if said at least one operation mode is on, wherein the sectional resultant regions are the divided regions of a resultant irradiated region that is a combination of the irradiated region of the left and right headlamps, the mode information includes a region ID code for each of the plurality of sectional resultant regions (1 to 23); a correspondence relation retention portion (114, 122) that retains the region ID code and a light source ID code that identifies one of the plurality of semiconductor light sources that illuminates the sectional resultant region identified by the region ID code, with the region ID code and the light source ID associated with each other; a state determination portion (110, 118) configured to refer to the correspondence relation retention portion (114, 112) to determine a state of each of the plurality of semiconductor light sources (34R/L-1 to 34R/L-20) based on which sectional resultant regions is specified by the mode information received by the mode information reception portion (108, 116), if the mode information received indicates that one of the at least one operation mode is on, wherein the state determination portion (110,118) is further configured to refer to the correspondence relation retention portion (114, 122) to determine at least one of the semiconductor light sources that is identified by the light source ID code corresponding to the region ID code included in the mode information, as the semiconductor light source whose luminance needs to be altered; and a light source control portion (112, 120) configured to control the plurality of semiconductor light sources (34R/L-1 to 34R/L-20) so as to cause each of the plurality of semiconductor light sources (34R/L-1 to 34R/L-20) to be brought into the state determined by the state determination portion (110, 118),