A steel plate having a yield stress of 460 MPa or more, a tensile strength of 570 MPa or more, an absorbed energy vE -40°C of a weld zone of 150 J or more, determined by producing a multilayer fill weld joint, using a single bevel groove, by submerged arc welding having a welding heat input of 35 kJ/cm and then measuring the absorbed energy vE -40°C at -40 °C with a Charpy impact test, using the weld bond on the straight side at the 1/4 position along the thickness of the steel plates as the notch position for the test, and determining the mean for three tests, a Crack Tip Opening Displacement (CTOD) value (δ -10°C) of a weld joint of 0.50 mm or more, determined at -10°C over the entire thickness of the steel plate, and a hardness of a central segregation area of the steel plate satisfying formula below, said steel plate comprising: a chemical composition consisting of, by mass%, C: 0.02 % to 0.08 %, Si: 0.01 % to 0.35 %, Mn: 1.4 % to 1.85 %, P: 0.007 % or less, S: 0.0035 % or less, Al: 0.010 % to 0.060 %, Ni: 0.5 % to 2.0 %, Mo: 0.10 % to 0.50 %, Nb: 0.005 % to 0.040 %, Ti: 0.005 % to 0.025 %, B: less than 0.0003 %, N: 0.002 % to 0.005 %, Ca: 0.0005 % to 0.0050 %, and O: 0.0030 % or less, and optionally at least one selected from the group consisting of: Cu: 0.7 % or less, Cr: 0.1 % to 1.0 %, and V: 0.005 % to 0.050 %, and a balance being Fe and incidental impurities, and wherein Ceq specified by formula below is from 0.420 to 0.520, Ti/N is from 1.5 to 4.0, and formulas and below are satisfied: Ceq = C + Mn / 6 + Cu + Ni / 15 + Cr + Mo + V / 5 0 < Ca − 0.18 + 130 × Ca × O / 1.25 / S < 1 5.5 C 4 / 3 + 15 P + 0.90 Mn + 0.12 Ni + 7.9 Nb 1 / 2 + 0.53 Mo ≤ 3.70 Hvmax / Hvave ≤ 1.35 + 0.006 / C − t / 500 where brackets [] indicate the content by mass% of the element in the brackets, where Hvmax is a maximum Vickers hardness of the central segregation area, Hvave is an average Vickers hardness of a portion excluding the central segregation area and sections from both front and back surfaces inward to 1/4 of a plate thickness, and t is the plate thickness of the steel plate in millimeters, and wherein the thickness of the steel plate is 35 mm to 100 mm. a chemical composition consisting of, by mass%, C: 0.02 % to 0.08 %, Si: 0.01 % to 0.35 %, Mn: 1.4 % to 1.85 %, P: 0.007 % or less, S: 0.0035 % or less, Al: 0.010 % to 0.060 %, Ni: 0.5 % to 2.0 %, Mo: 0.10 % to 0.50 %, Nb: 0.005 % to 0.040 %, Ti: 0.005 % to 0.025 %, B: less than 0.0003 %, N: 0.002 % to 0.005 %, Ca: 0.0005 % to 0.0050 %, and O: 0.0030 % or less, and optionally at least one selected from the group consisting of: Cu: 0.7 % or less, Cr: 0.1 % to 1.0 %, and V: 0.005 % to 0.050 %, and Cu: 0.7 % or less, Cr: 0.1 % to 1.0 %, and V: 0.005 % to 0.050 %, and a balance being Fe and incidental impurities, and wherein Ceq specified by formula below is from 0.420 to 0.520, Ti/N is from 1.5 to 4.0, and formulas and below are satisfied: Ceq = C + Mn / 6 + Cu + Ni / 15 + Cr + Mo + V / 5 0 < Ca − 0.18 + 130 × Ca × O / 1.25 / S < 1 5.5 C 4 / 3 + 15 P + 0.90 Mn + 0.12 Ni + 7.9 Nb 1 / 2 + 0.53 Mo ≤ 3.70 Hvmax / Hvave ≤ 1.35 + 0.006 / C − t / 500 where brackets [] indicate the content by mass% of the element in the brackets, where Hvmax is a maximum Vickers hardness of the central segregation area, Hvave is an average Vickers hardness of a portion excluding the central segregation area and sections from both front and back surfaces inward to 1/4 of a plate thickness, and t is the plate thickness of the steel plate in millimeters, and wherein the thickness of the steel plate is 35 mm to 100 mm.