Abstract: A powder consisting of barium titanate powder, strontium titanate powder or a solid solution thereof, characterized in that (a) its average particle diameter is 0.07 to 0.5.mu., (b) its specific surface area measured is 20 m.sup.2 /g or less and does not exceed 2.5 times the specific surface area calculated from the average particle diameter on the assumption that the powder particles are spherical, (c) its crystallite diameter calculated from the half-width of the peak of the X-ray diffraction pattern for the powder is 0.05.mu. or more, and (d) its shape is substantially spherical. Said powder can be produced by reacting hydrous titanium oxide with barium hydroxide and/or strontium hydroxide at a temperature ranging from 60.degree. C. to less than 110.degree. C. in the presence of 120 to 2,000 moles of water per mole of titanium.