The method of manufacturing a lithium silicate compound

Disclosed is a method for producing a lithium silicate compound, which is characterized in that a lithium silicate compound expressed as Li2SiO3 is reacted with a substance containing at least one transition metal element selected from a group consisting of iron and manganese at a temperature of 400-650 DEG C in a molten salt of a carbonate mixture which is composed of lithium carbonate and at least one alkali metal carbonate selected from a group consisting of potassium carbonate, sodium carbonate, rubidium carbonate and caesium carbonate, in a mixed gas atmosphere containing carbon dioxide and a reducing gas. Also disclosed is a positive electrode active material for a lithium ion secondary battery, which is composed of a lithium silicate compound obtained by the method. In the method of the present invention, a lithium silicate material which is useful as a positive electrode active material for a lithium ion secondary battery and the like can be produced by a comparatively simple means.