Disclosed herein is a stereomicroscope. The stereomicroscope comprises a microscope main body, a stand including a stand base portion on which a sample is to be laid, a support disposed vertically on the stand base portion, a focus adjust portion attached so as to be movable along the support, and an arm portion connected to the focus adjust portion for connecting the microscope main body thereto, so that the microscope main body is mounted on the stand to focus the sample, a light source lamp which illuminates the sample, and a light source unit in which the light source lamp is contained and which is attachable to at least one of the stand base portion, the support, and the arm portion.