Provided is an adaptor for attaching a portable terminal, said adaptor enabling a smartphone 3 to be simply attached to and detached from a microscope 4. The present invention is provided with a first adaptor 1 on the smartphone 3 side, and a second adaptor 2 on the microscope 4 side. The first adaptor 1 and the second adaptor 2 respectively have a first slide section 10 and a second slide section 20, 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 3 to and from the microscope 4.
