Context : Aims : We study the sub-AU-scale circumstellar environment of the Herbig Ae star HD144432 with near-infrared ( NIR ) VLTI/AMBER observations to investigate the structure of its inner dust disk . Methods : The interferometric observations were carried out with the AMBER instrument in the H and K band . We interpret the measured H - and K -band visibilities , the near- and mid-infrared visibilities from the literature , and the SED of HD144432 by using geometric ring models and ring-shaped temperature-gradient disk models with power-law temperature distributions . Results : We derived a K -band ring-fit radius of 0.17 \pm 0.01 ~ { } { \mathrm { AU } } and an H -band radius of 0.18 \pm 0.01 ~ { } { \mathrm { AU } } ( for a distance of 145 ~ { } { \mathrm { pc } } ) . This measured K -band radius of { \sim } 0.17 ~ { } { \mathrm { AU } } lies in the range between the dust sublimation radius of { \sim } 0.13 ~ { } { \mathrm { AU } } ( predicted for a dust sublimation temperature of 1500 ~ { } \mathrm { K } and gray dust ) and the prediction of models including backwarming ( { \sim } 0.27 ~ { } { \mathrm { AU } } ) . We found that an additional extended halo component is required in both the geometric and temperature-gradient modeling . In the best temperature-gradient model , the disk consists of two components . The inner part of the disk is a thin ring with an inner radius of { \sim } 0.21 ~ { } { \mathrm { AU } } , a temperature of { \sim } 1600 ~ { } \mathrm { K } , and a ring thickness { \sim } 0.02 ~ { } { \mathrm { AU } } . The outer part extends from { \sim } 1 ~ { } { \mathrm { AU } } to { \sim } 10 ~ { } { \mathrm { AU } } with an inner temperature of { \sim } 400 ~ { } \mathrm { K } . We find that the disk is nearly face-on with an inclination angle of < 28 { } ^ { \circ } . Conclusions : Our temperature-gradient modeling suggests that the NIR excess is dominated by emission from a narrow , bright rim located at the dust sublimation radius , while an extended halo component contributes { \sim } 6 \% to the total flux at 2 ~ { } { \mu \mathrm { m } } . The MIR model emission has a two-component structure with { \sim } 20 \% flux from the inner ring and the rest from the outer part . This two-component structure suggests a disk gap , which is possibly caused by the shadow of a puffed-up inner rim .