Development of a general and simple reaction by an organocatalyst and a transition-metal catalyst in cooperation is highly desirable for various organic syntheses but remains a challenge. Herein, we report the one-step synthesis of a ketone from an aldehyde by the combination of thiazolium N-heterocyclic carbene and palladium/bisphosphine catalysts in one flask. The two catalysts function in a synergistic manner. This study is expected to lead to new synthesis processes of precursor compounds for medications.