Training deep neural networks with empirical risk minimization (ERM) often captures dataset biases, hindering generalization to new or unseen data. Previous solutions either require prior knowledge of biases or utilize training intentionally biased models as auxiliaries; however, they still suffer from multiple biases. To address this, we introduce Adaptive Bias Discovery (ABD), a novel learning framework designed to mitigate the impact of multiple unknown biases. ABD trains an auxiliary model to be adapted to biases based on the debiased parameters from the debiasing phase, allowing it to navigate through multiple biases. Then, samples are reweighted based on the discovered biases to update debiased parameters. Extensive evaluations of synthetic experiments and real-world datasets demonstrate that ABD consistently outperforms existing methods, particularly in real-world applications where multiple unknown biases are prevalent.