A socket includes a first base member that includes a module mount unit allowing a module including an imaging device and an object to be placed thereon and an electric connector that electrically connects the imaging device to an external apparatus, a second base member having an opening, and an engagement unit that causes the first base member to be engaged with the second base member under a condition that the module placed on the module mount unit is sandwiched by the first and second base members. When the first base member is engaged with the second base member by the engagement unit under a condition that the module placed on the module mount unit is sandwiched by the first base member and the second base member, the electric connector is electrically connected to the imaging device, and the object receives illumination light from a light source through the opening.