The present invention relates to a high-concentration oxygen-dissolving apparatus using ultrasonic waves. More particularly, the present invention relates to a high-concentration oxygen-dissolving apparatus using ultrasonic waves in which, when liquid is introduced via an inlet port, a sediment filter filters out foreign substances, a pre-carbon filter filters out harmful chemical substances, a UF membrane filter filters out impurities, a post-carbon filter filters out gas components and odorous components, the filtered liquid is stored in a storage tank, the liquid stored in the storage tank passes through a cooling device to be cooled to a low temperature, the liquid compressed to high pressure by means of a high pressure pump and a Venturi tube is introduced into an ultrasonic wave irradiating unit, oxygen is dissolved into the liquid by ultrasonic waves irradiated from the ultrasonic wave irradiating unit, the liquid flows to the storage tank through a flow pipe, and the liquid having an oxygen concentration higher than a predetermined level is discharged through an outlet pipe.