Illumination device for microscope and microscope

An illumination device for a microscope includes: a lamp house configured to emit illumination light; and a turret having a first mirror unit for polarization observation and a second mirror unit for another observation method, the turret being configured to rotate the first and second mirror units on a plane perpendicular to an optical axis of an observation optical system of the microscope to position one of the first and second mirror units on the optical axis. The first mirror unit includes a polarizer and a mirror. The turret includes an analyzer arranged on an optical axis of the first mirror unit. The turret rotates the analyzer and the first mirror unit on the plane perpendicular to the optical axis of the observation optical system of the microscope while maintaining a positional relation between the analyzer and the first mirror unit.