An optically active form of the quinazolinone derivatives represented by the general formula (1): ##STR00001## [wherein Y represents a phenyl group or C2-C7 alkyl group; E represents --CH.dbd. or nitrogen atom; and R represents a C1-C4 alkyl group and so on], or pharmaceutically acceptable salts thereof, has a selective antagonism for the M3 muscarinic receptor and depressant action on the frequency of rhythmic bladder contractions, and it is useful for the treatment of pollakiuria and urinary incontinence.