Dual-camera electronic devices have the potential to deliver additional functionalities, such as depth acquisition and high dynamic range (HDR) imaging, more easily than those with a single camera. In this paper, we focus on the generation of a high dynamic range image for electronic devices equipped with a pair of parallel cameras that have different exposure time. Specifically, we propose a method that uses a long-exposure image to guide the enhancement of a short-exposure image. Unlike previous methods that are sensitive to stereo mismatch, which often occurs in the occluded regions, our method prevents the effect of inevitable disparity estimation errors on image synthesis and thereby enhances the robustness of HDR imaging. Experimental results show that our method generates higher quality HDR images without artifacts in the occluded regions.