A hot rolled steel sheet cooling apparatus includes a gradual cooling header 2 including a rod-like cooling water nozzle 3 for gradual cooling and a rapid cooling header 4 including a rod-like cooling water nozzle 5 for rapid cooling such that the headers constitute a cooling unit 9. The cooling unit 9 includes an elevating unit 7 capable of moving upward and downward in unison with the cooling unit. In cooling the upper surface of a hot rolled steel sheet (hot rolled steel strip or steel plate), uniform and stable cooling is achieved while both of high cooling rate and low cooling rate are ensured.