A liquid diffusion device, comprising: a liquid storage container for receiving liquid； a core capable of being putted into the liquid storage container for sucking the liquid within the liquid storage container； and a diffusion sheet being formed by a porous material, and installed at an upper side of the liquid storage container to be in contact with the core； thereby, the core can suck the liquid within the liquid storage container and then the liquid is transferred to the diffusion sheet continuously. The diffusion sheet is sintered glass with pores, or is formed by compressing and solidifying alloy powders with a plurality of pores for remaining therein. The outer container is installed with an upper cover which covers or screws on the outer container. The diffusion sheet has a regular shape or an irregular shape.
