Patent attributes
A microscope system includes a light source and an objective unit. The objective unit includes an objective optical system, including a small-diameter distal optical system arranged at an end brought near to or into contact with a specimen, for focusing light from the light source onto the specimen; a threaded mount at a coupling position; and an outer cylinder enclosing the small-diameter distal optical system. The microscope system further includes an imaging optical system for forming an image of light from the specimen through the objective optical system and a microscope main body for housing the imaging optical system. The objective unit is detachable from and attachable to the microscope main body with the threaded mount. Conditional expression Df/Da≦0.3 is satisfied, where Df represents the outer diameter of the outer cylinder and Da represents the outer diameter of the threaded mount.