A fixing assembly which is disposed on a vehicle and utilized for fixing a wheelchair is provided.The fixing assembly has a plurality of guide track and a plurality of slide block.The slide block has a body, a locking component and at least one elastic component.When the locking component is fixed on the guide track by a force formed by the elastic component, the slide block is fixed on the guide track.When the locking component is raised up by an external force, the slide block is adapted to escape from the guide track.一種固定器總成,係裝置於一行動載具以固定一輪椅,包含複數滑軌及複數滑塊。各滑塊具有一本體、一卡固件及至少一彈性件。其中,當卡固件因至少一彈性件之作用,而卡固於滑軌時,則滑塊適可被固定於滑軌上,而當卡固件受一外力作用上提,而未與滑軌接觸時,則滑塊適可與滑軌脫離。100‧‧‧固定器總成200‧‧‧滑軌210‧‧‧上端212‧‧‧間隙222‧‧‧滑槽300‧‧‧滑塊310‧‧‧本體312‧‧‧鎖固部320‧‧‧卡固件330‧‧‧彈性件332‧‧‧簧片