The invention provides a temperature-difference-resisting and pressure-difference-resisting writing tool. A writing part and an ink storage part are arranged at the two ends of a pen holder of the tool correspondingly, a pen point is locally inserted in the writing part, a first partition plate and a second partition plate of an adjusting part are arranged at an interval to form an air partition layer, an adjusting channel comprises a first ventilation pipe and a second ventilation pipe, the first ventilation pipe is arranged on the first partition plate, and the second ventilation pipe is arranged on the second partition plate; the first ventilation pipe and the second ventilation pipe are in inserted connection, and a first gap is arranged between the mutual inserted-connection portions; and the first partition plate is in contact with ink of the ink storage part, the second partition plate is close to the writing part, an ink feeder penetrates the adjusting part and the adjusting channel, a second gap is arranged between the ink feeder and the first partition plate, and an air guide pipe is arranged on the second partition plate and extends to the air partition layer. The temperature-difference-resisting and pressure-difference-resisting writing tool is large in ink capacity, small in amount of residual ink and smooth and even in writing, and even if the exterior temperature and the exterior pressure are greatly changed, ink is not prone to being leaked. The temperature-difference-resisting and pressure-difference-resisting writing tool is concise and stable in structure, resistant to pressure difference and temperature difference and convenient to transport; and the ink utilization rate is high, use is convenient, the waste is reduced, and environment pollutions are reduced.