A facility for manufacturing a steel plate comprising: a hot rolling apparatus, a shape correcting apparatus, a descaling apparatus and an accelerated cooling apparatus which are disposed in this order from an upstream side in a conveyance direction, the accelerated cooling apparatus including a header that supplies cooling water to an upper surface of the steel plate, and draining rollers set in front of and behind the header, characterised in that the descaling apparatus is arranged to jet cooling water towards a surface of a steel plate with an energy density E greater than or equal to 0.10 J/mm 2, wherein the energy density E is defined either: by E = Q/(d × W) × ρv 2 /2 × t, where Q: descaling water jetting flow rate [m 3 /s], d: spray jet thickness [mm] of flat nozzle, W: spray jet width [mm] of flat nozzle, p: fluid density [kg/m 3], v: fluid velocity [m/s] during collision at steel plate, and t: collision time [s]; or by water flow amount density × jetting pressure × collision time, wherein the water flow amount density [m 3 /(mm 2 ·min)] is calculated by jetting flow rate of cooling water ÷ cooling water collision area, the jetting pressure [MPa] is defined by ejection pressure of cooling water, and the collision time [s] is calculated by cooling water collision thickness ÷ transport velocity of the steel plate, the facility being further characterized in that the accelerated cooling apparatus further includes: cooling water injection nozzles that are arranged in rows, each row comprising cooling water injection nozzles arranged side by side in a width direction of the steel plate and suspended from the header, the cooling water injection nozzles in a most upstream side row being tilted upstream in the conveyance direction, and the cooling water injection nozzles in a most downstream side row being tilted downstream in the conveyance direction. a hot rolling apparatus, a shape correcting apparatus, a descaling apparatus and an accelerated cooling apparatus which are disposed in this order from an upstream side in a conveyance direction, the accelerated cooling apparatus including a header that supplies cooling water to an upper surface of the steel plate, and draining rollers set in front of and behind the header, characterised in that the descaling apparatus is arranged to jet cooling water towards a surface of a steel plate with an energy density E greater than or equal to 0.10 J/mm 2, wherein the energy density E is defined either: by E = Q/(d × W) × ρv 2 /2 × t, where Q: descaling water jetting flow rate [m 3 /s], d: spray jet thickness [mm] of flat nozzle, W: spray jet width [mm] of flat nozzle, p: fluid density [kg/m 3], v: fluid velocity [m/s] during collision at steel plate, and t: collision time [s]; or by water flow amount density × jetting pressure × collision time, wherein the water flow amount density [m 3 /(mm 2 ·min)] is calculated by jetting flow rate of cooling water ÷ cooling water collision area, the jetting pressure [MPa] is defined by ejection pressure of cooling water, and the collision time [s] is calculated by cooling water collision thickness ÷ transport velocity of the steel plate, the facility being further characterized in that the accelerated cooling apparatus further includes: cooling water injection nozzles that are arranged in rows, each row comprising cooling water injection nozzles arranged side by side in a width direction of the steel plate and suspended from the header, the cooling water injection nozzles in a most upstream side row being tilted upstream in the conveyance direction, and the cooling water injection nozzles in a most downstream side row being tilted downstream in the conveyance direction. by E = Q/(d × W) × ρv 2 /2 × t, where Q: descaling water jetting flow rate [m 3 /s], d: spray jet thickness [mm] of flat nozzle, W: spray jet width [mm] of flat nozzle, p: fluid density [kg/m 3], v: fluid velocity [m/s] during collision at steel plate, and t: collision time [s]; or by water flow amount density × jetting pressure × collision time, wherein the water flow amount density [m 3 /(mm 2 ·min)] is calculated by jetting flow rate of cooling water ÷ cooling water collision area, the jetting pressure [MPa] is defined by ejection pressure of cooling water, and the collision time [s] is calculated by cooling water collision thickness ÷ transport velocity of the steel plate, the facility being further characterized in that the accelerated cooling apparatus further includes: cooling water injection nozzles that are arranged in rows, each row comprising cooling water injection nozzles arranged side by side in a width direction of the steel plate and suspended from the header, the cooling water injection nozzles in a most upstream side row being tilted upstream in the conveyance direction, and the cooling water injection nozzles in a most downstream side row being tilted downstream in the conveyance direction.