To provide a spraying device and method to prevent the generation of powder dust, prevent the occurrence of lowering of working efficiency due to choking of a nozzle and the decrease of a delivery amount, and provide stable workability under excellent work environment.

A wet material spraying device comprises a feeding part 12 for a monolithic refractory material in a dry state; a material mixing part 14 to mix a material with water; a mixture material feeding part 16 to feed a material, brought into a wet state by mixing with water, to a spraying means, and a nozzle part 18 to spray a material against a given surface of a structure. The mixture material feed part 16 comprises a forced feed pump 46; and a pressure air valve 52 for forced feed to feed high pressure air. The nozzle part 18 comprises a spray nozzle 60, and a pressure air valve 62, and air 56 is intervened in a refractory material 54. The refractory material 54 is injected through the nozzle 60 by a composite press force of a mechanical press force by the pump 46 and a pneumatic press force from the valve 52.