PROBLEM TO BE SOLVED: To provide a plate-end processing method which enables thread-chamfering at a 0.5 mm or less width to precisely and uniformly be performed without performing pretreatment such as masking.SOLUTION: A slit nozzle 20 with a slit-like opening 21 is placed such that a longitudinal direction of the slit-like opening 21 extends along a longitudinal direction of an edge 11 formed along an end of a plate 10, and such that a distance D [refer to Fig.2(A)] between the tip of the slit nozzle 20 and an apex of the edge 11 is 3 mm or less. An abrasive with a grit number 600 or less grit diameter (a grit number 600 or higher number abrasive) is ejected at an ejection pressure of 0.1 to 0.5 MPa toward the edge 11 through the slit nozzle 20; and the ejected abrasive, the abrasive and cut dusts adhered to the plate 10 are collected by suction from a front side in an ejecting direction of the abrasive at an average wind speed of 30 m/sec or higher.