An apparatus for producing a porous body that forms an expandable slurry containing at least inorganic powder, a foaming agent, and a binder into a sheet, causes the expandable slurry sheet to be foamed and baked, and thereby produces the porous body, the apparatus includes: a mixer preparing the expandable slurry by containing inorganic powder, a foaming agent, and a binder; a die-coater that has a discharge opening which discharges the expandable slurry provided from the mixer to an external thereof so as to shape the expandable slurry into a sheet; and a carrier sheet arranged so as to face the discharge opening of the die-coater with a gap interposed therebetween, and feeding the expandable slurry discharged from the discharge opening, wherein a flow path of the expandable slurry from inside the mixer to the discharge opening of the die-coater is hermetically sealed from an outside.