Equipment for dissolving polyacrylamide powder to obtain an aqueous solution thereof for enhanced oil recovery comprisesfirst and second powder storage tanks for storing polyacrylamide powder under nitrogen atmosphere;a gas conveyor unit for carrying the polyacrylamide powder from the first storage tank to the second storage tank by nitrogen gas flow;a constant powder supply unit for receiving the polyacrylamide powder from the second storage tank, metering the powder, and sending the metered powder toa powder dispersion unit for dispersing in water the polyacrylamide powder.A first liquid supply unit sends the dispersion or solution of polyacrylamide powder obtained from the powder dispersion unit to a dissolution tank for completing dissolution of the polyacrylamide;and a second liquid supply unit transfers the polyacrylamide solution from the dissolution tank to a solution storage tank for storing the polyacrylamide solution.A filtration unit is connected in the liquid supply line between the dissolution tank and the solution storage tank; anda nitrogen gas supply system maintains the interiors of these units filled with nitrogen gas at a pressure higher than atmospheric pressure.