The purpose of this research is to calculate the restoring force characteristics of a panel with a solid wood board fitted to timber grid. Diagonal compression experiments were conducted using existence or nonexistence of the solid wood board and cross section size of the timber grid as parameters. The restoring force characteristics of the timber grid panel can be evaluated by the calculation formula of the previous study. The restoring force characteristic could be calculated by adding the shear strength which the timber grid can withstand the shear strain which the solid board obtained from the shear strain adds together.
