To provide a calendar with a cassette case that prevents forgetting of taking or taking twice of medicines by making cohabitation family understandable of a taking status of medicines at a glance without relying on a vague memory of a patient, since prescription medicines of geriatric diseases are normally provided in a batch of 28 days or 30 days in one lot, and if a patient takes many kinds of medicines at designated times each day, while keeping them together in a same bag, the patient may frequently make mistakes to forget taking or taking twice.

In a base of a monthly calendar which can display any month, days of the week are written, and under where a roll type date display belt that can be rotated with a finger is provided, and further under where a transparent and openable type cassette case is installed, and the medicine is subdivided into a dosage for only one day and kept therein. By making two units into one set, this monthly calendar can cope with starting of taking medicine from any date of any year, and forgetting to take internal medicine and taking twice can be prevented.