A nano-bubble water generating apparatus containing an application gas includes a motor, a pump integrated with the motor for supplying liquid, typically water, from an inlet pipe under a predetermined pressure through a supplying pipe to a pressure tank, a nano-bubble water generating tube mounted at the water entrance of a pressure tank, an electronic control portion, a pressure adjuster including an outer air inflowing portion to introduce an outer air or a specific gas supplied thereinto to control a pressure in the pressure tank, uniformly and a pressure adjusting portion airtightly coupled on the upper portion of the outer air inflowing portion to adjust an amount of outer air or specific gas to be supplied, and a nano-bubble water expanding tube for expanding and shattering nano-bubble water through an outlet pipe from the pressure tank, so that the size of the nano-bubble water is better micronized.