Steel plate and a manufacturing method thereof excellent in multilayer welded joint ctod characteristics

Providing steel plate and a manufacturing method thereof excellent in multilayer welded joint CTOD properties of small to intermission heat. In mass%, the component composition, C: 0.03~0.12%, Si: 0.5% or less, Mn: 1.0~2.0%, P: 0.015% or less, S: 0. 0005~0.0050%, Al: 0.005~0.060%, Ni: 0.5~2.0%, Ti: 0.005~0.030%, N: 0.0015~0.0065% , O: 0.0010~0.0050%, Ca: 0.0005~0.0060%, optionally comprises one or more of Cu, etc., Ti / N, Ceq, the Pcm and ACR value in a specific range, below 20μm is effective crystal grain size of the base material in the thickness center, the circle formed of an oxide containing sulfide and Al containing Ca and Mn in the respective thickness of 1/4 to 1/2 steel sheet equivalent diameter 0.1μm or more composite inclusions are present certain amount. The steel of the above composition, after heating at a specific temperature, hot rolling and cooling.