The present invention provides and produces a high-grade layered double hydroxide (LDH) dense body having a relative density of 88% or greater in a simple and stable manner. The present invention provides a LDH dense body including a layered double hydroxide as a main phase and having a relative density of 88% or greater, the LDH being represented by general formula: M2+1-xM3+x(OH)2An−x/n.mH2O wherein M2+ is a divalent cation, M3+ is a trivalent cation, An− is an n-valent anion, n is an integer of 1 or greater, and x is 0.1 to 0.4. This LDH dense body can be produced by compacting and firing a raw material powder of a LDH to obtain an oxide fired body, retaining this oxide fired body in or immediately above an aqueous solution comprising an n-valent anion to reproduce the LDH, and removing excessive water from the resulting water-rich LDH solidified body.