Title: Task Regularized Hybrid Knowledge Distillation For Continual Object Detection. Abstract: Knowledge distillation has been used to overcome catastrophic forgetting in Continual Object Detection(COD) task. Previous works mainly focus on combining different distillation methods, including feature, classification, location and relation, into a mixed scheme to solve this problem. In this paper, we propose a task regularized hybrid knowledge distillation method for COD task. First, we propose an image-level hybrid knowledge representation by combining instance-level hard and soft knowledge to use teacher knowledge critically. Second, we propose a task-based regularization distillation loss by taking account of loss and category differences to make continual learning more balance between old and new tasks. We find that, under appropriate knowledge selection and transfer strategies, using only classification distillation can also relieve knowledge forgetting effectively. Extensive experiments conducted on MS COCO2017 demonstrate that our method achieves state-of-the-art results under various scenarios. We get an absolute improvement of 27.98 at $RelGap$ under the most difficult five-task scenario. Code is in attachment and will be available on github.