A high-strength and high-rigidity steel plate consisting of 0.05% to 0.4% by mass of C, 1.65% by mass or less of Mn, 0.55% by mass or less of Si,. 0.040% by mass or less of P, and 0.30% by mass or less of S, with the balance being Fe and inevitable impurities, wherein, a plate thickness center portion being in a range to be one-third in a plate thickness direction, t × 1/3 to t × 2/3, with a half of a plate thickness, t, as a center, a surface layer portion being in a range to be one-third in the plate thickness direction, t × 0/3 to t × 1/3, with respect to an upper surface and another surface layer portion is in a range to be one-third in the plate thickness direction, t × 3/3 to t × 2/3, with respect to a lower surface, an average grain size of the metallographic structure at the plate thickness center portion is in a range of 0.8 μm to 2.0 μm, the average grain size of the metallographic structure at the surface layer portion is in a range of 0.3 μm to 2.0 μm, and an estimated value of Young's modulus obtained according to the following formula at the plate thickness center portion or the surface layer portion is 210 GPa or more: estimated value of Young ′ s modulus = f 001 × 132 GPa + f 111 × 283 GPa + 1 − f 001 − f 111 × 208 GPa where f 001 represents an accumulation rate of a <001> orientation with respect to a load axis, f 111 represents an accumulation rate of a <111> orientation, and (1-f 001 -f 111) represents an accumulation rate of crystal orientations except the <001> orientation and the <111> orientation, and a yield strength measured by a tensile test using a test piece cut from the steel plate at the plate thickness center portion or surface layer portion is 580 MPa or more. 0.05% to 0.4% by mass of C, 1.65% by mass or less of Mn, 0.55% by mass or less of Si,. 0.040% by mass or less of P, and 0.30% by mass or less of S, with the balance being Fe and inevitable impurities, wherein, a plate thickness center portion being in a range to be one-third in a plate thickness direction, t × 1/3 to t × 2/3, with a half of a plate thickness, t, as a center, a surface layer portion being in a range to be one-third in the plate thickness direction, t × 0/3 to t × 1/3, with respect to an upper surface and another surface layer portion is in a range to be one-third in the plate thickness direction, t × 3/3 to t × 2/3, with respect to a lower surface, an average grain size of the metallographic structure at the plate thickness center portion is in a range of 0.8 μm to 2.0 μm, the average grain size of the metallographic structure at the surface layer portion is in a range of 0.3 μm to 2.0 μm, and an estimated value of Young's modulus obtained according to the following formula at the plate thickness center portion or the surface layer portion is 210 GPa or more: estimated value of Young ′ s modulus = f 001 × 132 GPa + f 111 × 283 GPa + 1 − f 001 − f 111 × 208 GPa where f 001 represents an accumulation rate of a <001> orientation with respect to a load axis, f 111 represents an accumulation rate of a <111> orientation, and (1-f 001 -f 111) represents an accumulation rate of crystal orientations except the <001> orientation and the <111> orientation, and a yield strength measured by a tensile test using a test piece cut from the steel plate at the plate thickness center portion or surface layer portion is 580 MPa or more.