The present invention is a safer CO2 hydrate for oral intake that has sufficient carbon dioxide sensation while reducing the risk of carbon dioxide poisoning when it is taken into the mouth after being added to food or drink or when taken directly into the mouth. And the production method thereof, and in particular, CO2 so that the maximum CO2 generation rate at the time of melting of CO2 hydrate under an environment similar to that in the human oral cavity is less than 8 mL / second. An object of the present invention is to provide a CO2 hydrate for ingestion of the oral cavity in which sustained release is adjusted, a production method thereof, and the like. The CO2 hydrate is adjusted so that the maximum CO2 generation rate is less than 8 mL / second. (Definition of maximum CO2 generation rate (mL / sec)) CO2 hydrate containing 0.3 to 0.36 g of CO2 was fractionated, and the fractionated CO2 hydrate was separated at room temperature of 37 ° C. and humidity of 70%. In an atmosphere of atmospheric pressure, it was added to 10 mL of water at a liquid temperature of 37 ° C., and the change in weight was measured at least 30 seconds every 5 seconds after the addition, and the amount of CO 2 generated (mL) every 5 seconds was measured. The test of calculating and calculating the CO2 generation rate (mL / second) every 5 seconds from the generated amount (mL) was repeated three times, and the obtained CO2 generation rate (mL / second) every 5 seconds. The maximum value is taken as the maximum CO2 generation rate (mL / sec) of the CO2 hydrate.本発明は、飲食品に添加してから口腔摂取する場合や、直接口腔摂取する場合の二酸化炭素中毒リスクを低減しつつ、十分な炭酸感を有する、より安全性の高い口腔摂取用ＣＯ２ハイドレート等、及び、それらの製造方法等を提供することを目的とし、特に、ヒト口腔内に類似する環境下でのＣＯ２ハイドレートの融解時の最大ＣＯ２発生速度が８ｍＬ／秒 未満となるようにＣＯ２徐放性が調整された口腔摂取用ＣＯ２ハイドレート等、及び、それらの製造方法等を提供することを目的とする。 最大ＣＯ２発生速度が、８ｍＬ／秒 未満となるようにＣＯ２ハイドレートを調整することを特徴とする。（最大ＣＯ２発生速度（ｍＬ／秒）の定義）０．３～０．３６ｇのＣＯ２を含有する量のＣＯ２ハイドレートを分取し、分取したＣＯ２ハイドレートを、室温３７℃、湿度７０％の大気圧の雰囲気下で、液温３７℃の１０ｍＬの水に添加し、添加から５秒毎に少なくとも３０秒以上重量変化を測定して、５秒毎のＣＯ２の発生量（ｍＬ）をそれぞれ算出
