Provided are a thermal expansion suppressing member having negative thermal expansion properties and a metal-based anti-thermally-expansive member having small thermal expansion. More specifically, provided are a thermal expansion suppressing member, including at least an oxide represented by the following general formula (1), and an anti-thermally-expansive member, including a metal having a positive linear expansion coefficient at 20° C., and a solid body including at least an oxide represented by the following general formula (1), the metal and solid being joined to each other: (Bi1-xMx)NiO3 (1) where M represents at least one metal selected from the group consisting of La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, and In; and x represents a numerical value of 0.02≦x≦0.15.