An eco-friendly blood pressure monitor with a solar panel and rechargeable batteries. It has been developed for medical activities in difficult situations to get power such as in developing countries or disaster areas. It is both drip-proof and dust-proof for outdoor use. The battery provides more than 300 times of measurement on a full charge. Laying out the operation function and solar-generation function on separate surfaces of the monitor allowed improvement both for the operability and the charging efficiency with suitable angle for the sunlight. Its simple shape expresses the sense of reliability and cleanliness as a medical device.