Provided is an ultrafine bubble generation device for aquaculture or wastewater treatment with which it is possible to efficiently cause ultrafine bubbles to be dissolved or to coexist, and to increase the concentration of a gas in the liquid. An ultrafine bubble generation device for aquaculture or wastewater treatment provided with a channel for channeling a liquid, a compression device for pumping a gas into the channel, and a bubble generation medium for releasing the gas pumped by the compression device as ultrafine bubbles into the liquid in the channel, wherein the bubble generation medium is formed from a carbon-based porous material and is disposed so as to be horizontal or below horizontal with respect to the direction of flow of the liquid in the channel.
