PURPOSE: A seal hermetic water supplying apparatus is provided to enable the natural circulation of the hermetic water inside a coolant pump by the temperature difference of the coolant water and the hermetic water, by injecting the hermetic water into a hermetic water injection path after cooling the coolant water within a coolant pump chamber. CONSTITUTION: A seal hermetic water supplying apparatus is comprised of the followings: a coolant pump (100) which is able to include a first port (101) and a second port (102); a pump housing (105) in which including the coolant water leakage entrance is possible; a first fluid path (200) in which the hermetic water is flowed in from the outside to the coolant pump; a second fluid path (300) which is formed to enable the natural circulation of the seal hermetic water a third fluid path (400) which supplies the coolant water to the first fluid path when the coolant pump is not driving; and a fourth fluid path (500).
