the present invention relates to a button - sliding - type opening / closing device for a cosmetic container consisting of a vessel for storing cosmetics in a liquid or gel state , and a discharge pump coupled to a top inner portion of the vessel for discharging cosmetics by applying external pressure thereto , wherein the button - sliding - type opening / closing device comprises : a shoulder coupled to the top portion of the vessel ; a button body inserted into the shoulder and upwardly and downwardly movable ; and a button slidably coupled to a top surface of the button body , for opening and closing a cosmetic pumping hole in the button body , as well as for preventing the button body from being pressed and actuated .