A thin-film capacitor(2) in which a lower electrode(6), a dielectric thin-film(8), and an upper electrode(10) are formed in order on a substrate(4). The dielectric thin-film(8) is made of a composition for thin-film capacitance devices. The composition includes a bismuth layer-structured compound whose c-axis is oriented vertically to the substrate surface and which is expressed by a formula: (Bi.sub.2O.sub.2).sup.2+(A.sub.m-1B.sub.mO.sub.3m+1).sup.2-, or Bi.sub.2A.sub.m-1B.sub.mO.sub.3m+3 wherein "m" is an odd number, "A" is at least one element selected from Na, K, Pb, Ba, Sr, Ca and Bi, and "B" is at least one element selected from Fe, Co, Cr, Ga, Ti, Nb, Ta Sb, V, Mo and W. Even if the dielectric thin-film is made more thinner, the dielectric constant is relatively high, and the loss is small. The leak characteristics are excellent, the temperature characteristics of the dielectric constant are excellent, the break-down voltage is improved and the surface smoothness is excellent.