The invention discloses a fluid filtering apparatus. The apparatus comprises a box, and an input-pressure-equalizing pipe, an output-pressure-equalizing pipe, a plurality of air filters, an input pressure gauge, and an output pressure gauge that are arranged in the box to increase a removal fluid amount by filtration. The apparatus adapts to removal by filtration with a large flow-discharge amount, and allows an input amount and output amount almost to be kept consistent. Furthermore, a head of the input pressure gauge and a head of the output pressure gauge are arranged outside an accommodating space in the box, so that a user can learn the pressure states in the input-pressure-equalizing pipe and the output-pressure-equalizing pipe to perform corresponding measures.