1. A designing method of a glass-plate-aimed bending mold making use of a 3-dimensional CAD application for solid models, said method comprising the steps of: providing bending-shape data of a first glass plate targeted by a bending mold to be designed; retrieving an existing solid-model of a bending mold from a solid model database; replacing, bending-shape data of a second glass plate as a basis for constructing the existing solid-model, with the bending-shape data of the first glass plate; remodeling the existing solid-model to generate a first solid model of a bending mold for the first glass plate, by automatically modifying designed values required to be modified and by automatically inheriting designed values unrequired to be modified due to the step of replacing the bending-shape data of the second glass plate with the bending-shape data of the first glass plate, for the designed values possessed by the existing solid-model; judging whether predetermined design criteria are satisfied by values of predetermined modifiable parameters among the designed values inherited by the first solid model from the existing solid-model, or not; when the values of the predetermined modifiable parameters do not satisfy the predetermined design criteria; modifying the values of the predetermined modifiable parameters, and automatically modifying other designed values required to be modified due to the modifying the values of the predetermined modifiable parameters; and repeating the modifying the values of the predetermined modifiable parameters until the predetermined design criteria are satisfied; and when the values of the predetermined modifiable parameters satisfy the predetermined design criteria, creating bending-mold fabricating data based on data of the first solid model.