The present invention provides rapid disintegrating tablets in oral cavity having a shortened disintegration time in oral cavity as well as a sufficient hardness with compared to rapid disintegrating tablets of the prior art.The above objective is solved by a composition for rapid disintegrating tablets in oral cavity, wherein components (a) to (c) are contained in such manner that (a) saccharides consisting of a combination of mannitol and xylitol is 40 to 90 parts by weight; (b) the inorganic excipient is 1 to 30 parts by weight; and (c) the disintegrating agent is 5 to 40 parts by weight, provided that the total amount of (a), (b) and (c) is 100 parts by weight.