Method of grinding multilayer body and method of manufacturing solid state image pickup device

A method of grinding a multilayer body which can prevent a substrate from being damaged by a broken piece of a planar substance, which occurs during grinding and cutting in grinding and cutting the planar substance of the multilayer substance constructed by the substrate and the planar substance which are joined with an extremely narrow gap portion therebetween is provided. A protection layer of the substrate is formed in the gap portion in advance and the substrate can be prevented from being damaged by the broken piece of the planar substance occurring by grinding, in grinding and cutting the planar substance by cutting into the gap portion with a grindstone, of the multilayer body in which the substrate and the planar substance are joined to have the gap portion therebetween.