A computer-implemented metal sheet bending fracture determination method comprising: calculating a bending fracture limit stress for each of a bending amount R/t 0 obtained by dividing the bend radius R at sheet thickness center of a metal sheet by the initial sheet thickness t 0 of the metal sheet, the bending fracture limit stress being obtained as a value of σ 1 that satisfies a necking occurrence condition of dσ 1 /dε 1 = σ 1, wherein σ 1 is a true stress in a plane strain tension direction of a bend surface and is given by an equation of σ 1 = q(t 0 /t), wherein ε 1 is a tensile strain corresponding to the post-bending deformation sheet thickness t and is given by an equation of ε 1 = -ln(t/t 0) and q is an acting tensile force; calculating a fracture limit curve L1 for a uniform deformation state in space of stresses under the assumption of static strain rate and calculating a fracture limit stress under plane strain deformation, from work hardening characteristics obtained by uniaxial tensile testing of a material configuring the metal sheet; determining a ratio between the bending fracture limit stress σ cr corresponding to the bending amount R/t 0 of an element subject to determination in the metal sheet and the fracture limit stress under plane strain deformation, and calculating a fracture limit curve L2 corresponding to the bending amount R/t 0 by multiplying a stress component of the fracture limit curve L1 in the uniform deformation state by the ratio between the bending fracture limit stress corresponding to the bending amount R/t 0 of the element subject to determination in the metal sheet and the fracture limit stress under plane strain deformation; calculating a corresponding fracture limit stress from stress of the element subject to determination and the fracture limit curve L2 corresponding to the bending amount R/t 0; computing a risk ratio that is a ratio between the stress of the element subject to determination and the fracture limit stress calculated from the stress of the element subject to determination and the fracture limit curve L2 corresponding to the bending amount R/t 0; and performing fracture determination for the element subject to determination based on the risk ratio. calculating a bending fracture limit stress for each of a bending amount R/t 0 obtained by dividing the bend radius R at sheet thickness center of a metal sheet by the initial sheet thickness t 0 of the metal sheet, the bending fracture limit stress being obtained as a value of σ 1 that satisfies a necking occurrence condition of dσ 1 /dε 1 = σ 1, wherein σ 1 is a true stress in a plane strain tension direction of a bend surface and is given by an equation of σ 1 = q(t 0 /t), wherein ε 1 is a tensile strain corresponding to the post-bending deformation sheet thickness t and is given by an equation of ε 1 = -ln(t/t 0) and q is an acting tensile force; calculating a fracture limit curve L1 for a uniform deformation state in space of stresses under the assumption of static strain rate and calculating a fracture limit stress under plane strain deformation, from work hardening characteristics obtained by uniaxial tensile testing of a material configuring the metal sheet; determining a ratio between the bending fracture limit stress σ cr corresponding to the bending amount R/t 0 of an element subject to determination in the metal sheet and the fracture limit stress under plane strain deformation, and calculating a fracture limit curve L2 corresponding to the bending amount R/t 0 by multiplying a stress component of the fracture limit curve L1 in the uniform deformation state by the ratio between the bending fracture limit stress corresponding to the bending amount R/t 0 of the element subject to determination in the metal sheet and the fracture limit stress under plane strain deformation; calculating a corresponding fracture limit stress from stress of the element subject to determination and the fracture limit curve L2 corresponding to the bending amount R/t 0; computing a risk ratio that is a ratio between the stress of the element subject to determination and the fracture limit stress calculated from the stress of the element subject to determination and the fracture limit curve L2 corresponding to the bending amount R/t 0; and performing fracture determination for the element subject to determination based on the risk ratio.