When an employer makes a worker work overtime, or work on a day off under the provisions of Article 33 of the Act or paragraph (1) of Article 36 of the Act, or during the period between 10 p.m. and 5 a.m. (between 11 p.m. and 6 a.m. in areas or during periods specified by the Minister of Health, Labour and Welfare when the Minister finds it necessary), the number of overtime hours, that of working hours on days off or that of night working hours