To obtain a preparation orally administered which is regulated in releasing an analgesic from microtablets, permits the dose equal to individually and accurately releasing a drop agent from a storage medical case and can be distributed to the number of base capable of readily and accurately regulating a prescribed amount of an effective substance.

The objective preparation which is regulated in releasing at least one kind of analgesics from microtablets with a diameter not more than 3 mm (preferably a diameter of 1-3 mm, preferably in particular 1.5-3 mm) is obtained. It is favorable that the analgesic is comprised of at least one kind of opioids (e.g. hydromorphone, oxycodone, morphine, levorphanol, methadone, dihydrocodein or the like), the microtablet contains an analgesic homogeneously dispersed in a sustained-release matrix and the matrix includes at least one kind of polymers (e.g. cellulose ether and the like), waxes, fats, oils, fatty alcohols or their correspondent esters.