Abstract: Provided is an adaptor for attaching a portable terminal, said adaptor enabling a smartphone to be simply attached to and detached from a microscope. The present invention is provided with a first adaptor on the smartphone side, and a second adaptor on the microscope side. The first adaptor and the second adaptor, respectively have a first slide section and a second slide section, which are fitted to each other such that, in the straight line direction, the first slide section and the second slide section can mutually slide and can be attached to and detached from each other. As a result, the present invention makes it possible to easily attach and detach the smartphone to and from the microscope.