A substantial proportion of patients with Lewy body disease experience a variety of false perceptions, which include visual hallucinations of persons and animals, a sense of presence, passage hallucinations and various types of visual illusions. My colleagues and I have been conducting behavioral and neuroimaging studies to investigate common mechanisms underlying these phenomenologically diverse misperception symptoms. In this paper, I present the findings obtained from these studies and discuss psychological and neural mechanisms of false perceptions in Lewy body disease with referring to the concept of “sense of veridicality”.