An operation device includes: a communication unit that receives signals of images of a biological sample and outputs data to a display medium, the images being captured by a microscope that converts a phase distribution into an image intensity distribution; and a calculator that calculates a first phase distribution of the biological sample from the image signals. The calculator extracts a region having a phase amount that is not less than a specified phase amount from the first phase distribution, and generates evaluation information by using the region having a phase amount that is not less than the specified phase amount, that is an indicator used when a user evaluates a state of the biological sample; and the communication unit outputs the evaluation information to the display medium.