The present invention relates to: a steel sheet surface treatment device comprising a transport unit for transporting a steel sheet, and a laser line irradiation unit positioned on the transport route of the steel sheet and irradiating a laser line on the surface of the steel sheet in the shape of a line with respect to the width direction of the steel sheet; and a steel sheet surface treatment method comprising the steps of, by using the steel sheet surface treatment device, preparing a steel sheet and consecutively transporting same, and treating the surface of the steel sheet by irradiating, on the surface of the consecutively transported steel sheet, a laser line in the shape of a line with respect to the width direction of the steel sheet.
