An aqueous patch containing diclofenac sodium, wherein the patch contains a homogeneous mixed solution of diclofenac sodium, wherein the solution is obtained by mixing crotamiton, diclofenac sodium and water in the mixture ratio of crotamiton/diclofenac sodium of 8.0 or less and the mixture ratio of (water+crotamiton)/diclofenac sodium of 3.0-20.0.