A positive photoresist composition comprising (A) an alkali-soluble resin and (B) a light-sensitive component comprising at least one compound represented by the following general formula (I): ##STR1## where R.sup.1, R.sup.2 and R.sup.3 are each independently a hydrogen atom, an alkyl group having 1-3 carbon atoms or an alkoxy group having 1-3 carbon atoms; R.sup.4 is a hydrogen atom or an alkyl group having 1-3 carbon atoms; a, b and c are an integer of 1-3; l, m and n are an integer of 1-3, in which at least part of the hydroxyl groups present are esterified with a quinonediazidosulfonic acid and a sulfonic acid which has a group represented by the following formula (II): --SO.sub.2 --R.sup.5 (II) where R.sup.5 is a substituted or unsubstituted alkyl group, an alkenyl group or a substituted or unsubstituted aryl group, thereby forming a mixed ester, and a multilayer resist material in which a positive photoresist layer formed of said positive photoresist composition is provided on an anti-reflective coating over a substrate are capable of forming high-resolution resist patterns with good cross-sectional profiles and permit a wider margin of exposure and better depth-of-focus characteristics.