The invention provides an absorbing type water cooling-heating apparatus which employs an electrically-operated valve and an improved method of diluting a solution for automatically changing between heating operation and cooling operation only by operating a cooling-heating change-over switch. The apparatus comprises an evaporator for evaporating a cooling medium to cool cooling water, an absorber for causing a solution to absorb steam of the cooling medium evaporated in the evaporator to dilute the solution, a high-temperature regenerator and a low-temperature regenerator for concentrating the dilute solution, fed thereto from the absorber, by forming steam of the cooling medium, a condenser for condensing the steam of the cooling medium, produced in the low-temperature regenerator, into a liquid, a solution circulating pump for circulating the solution, a cooling medium spray pump for spraying the cooling medium, a cooling medium steam pipe connecting the interior of the high-temperature regenerator, in which the cooling medium steam is contained, to the interior of the evaporator in which the cooling medium is sprayed, a throttle device provided in the cooling medium steam pipe, an electrically-operated valve provided in the cooling medium steam pipe, and a cooling-heating change-over switch connected to the electrically-operated valve for switching the electrically-operated valve when changing the operation of the apparatus between a cooling mode and a heating mode.