A functional module type medical apparatus for use in medical treatment and/or diagnosis and a functional module with individual function of medical treatment and/or diagnosis are disclosed.The functional module type medical apparatus comprises a common functional body with a module connection part, having at least one of a display section for displaying necessary information relating to medical treatment and/or diagnosis, an operation section for medical treatment and/or diagnosis, and a power source section for supplying driving power to the medical apparatus, in which the module connection part is constructed such that the corresponding connection part of a functional module having medical treatment and/or diagnosis is replaceably connected thereto, whereby the common functional body cooperatively functions in accordance with its individual function of the functional module when the functional module is connected thereto.