A lateral protecting mechanism is disposed on a lateral wing of a child safety seat. The lateral protecting mechanism includes a lateral protecting block and a protecting component. An end of the lateral protecting block is pivoted to the lateral wing. The lateral protecting block is movable between a using position and a folding position. The protecting component is slidably disposed on the other end of the lateral protecting block. The protecting component protrudes from a side of the lateral protecting block and is located between the lateral wing and the lateral protecting block when the lateral protecting block rotates away from the lateral wing and is located at the using position, and the protecting component is received in the side of the lateral protecting block when the lateral protecting block rotates toward the lateral wing and is located at the folding position.