A method of setting a cutting time of a gasket during manufacture of a membrane electrode assembly (MEA) is provided. The method includes: moving a reaction sheet, in which electrode layers are formed on an electrolyte membrane with a predetermined interval; photographing a boundary area between the electrolyte membrane and the electrode layer in the moving reaction sheet by using a fixed vision; setting a front end reference line and a rear end reference line between a front-most end and a rear-most end in the boundary area; calculating a trigger reference line between the front end reference line and the rear end reference line, except for a front portion of the front end reference line and a rear portion of the rear end reference line; and calculating a cutting time of a gasket based on the trigger reference line.