Provided is a lateral water intake structure for preventing silting of bed load and floating debris, which is provided at a river bank. The lateral water intake structure includes: a diversion canal, a guiding wall structure, a shaft-shaped water intaking space, and a trash rack. The lateral water intake structure functions to prevent the floating debris from gathering at the surface of the trash rack and reduce a risk that the trash rack is damaged by water pressure and hitting of the floating debris. Meanwhile, by using a water flow in the watercourse to continuously wash the floating debris near the trash rack, maintenance costs of removing the floating debris at the trash rack manually or mechanically can be reduced.