It is an object of the present invention to provide a visibility-ensuring material which is capable of ensuring a surgical field for a predetermined time period, which does not inhibit the transmission of light, and which is capable of ensuring the visibility with which even delicate operations can be satisfactorily performed. A visibility-ensuring material of the present invention includes a gel-like viscoelastic body and has a storage elastic modulus during use of from 40 Pa to 700 Pa. A discharge device for a visibility-ensuring material of the present invention includes: a syringe； and at least one kind selected from the group consisting of a mesh filter, a needle, and an application nozzle.
