An aluminum complex hydroxide salt having Al oxide octahedral layers and a divalent anion among the octahedral layers, wherein an aluminosilicate anion expressed by the following general formula (1), [Na.sub.pAl.sub.qSi.sub.rO.sub.z].sup.2- (1) wherein p, q, r and z are positive numbers satisfying, 5.ltoreq.z.ltoreq.20, z=(p/2)+(3q/2)+2r+1, 0