A grating (1) and a method of manufacturing the same using a pressing process are disclosed. The grating manufacturing method of the present invention includes the step of bending opposite ends of a metal plate to form a main surface (5) and supports (4), each having a predetermined height, the step of drawing a plurality of water drain slot formation portions of the main surface (5) to form slot frame parts (3), each having a predetermined depth, and the step of perforating bottoms of the slot frame parts (3) to form water drain slots (2). Therefore, the present invention provides a grating (1) that can sustain a relatively heavy load despite being manufactured through a simple pressing process, and a method of manufacturing the same through the pressing process.