Indan derivatives of the formula: ##STR1## wherein R.sup.1 is substituted or unsubstituted phenyl, naphthyl or sulfur-containing heterocyclic group, and R.sup.2 is hydroxy-methyl or a group of the formula: ##STR2## wherein R.sup.3 is hydrogen atom or lower alkyl and R.sup.4 is cycloalkyl, lower alkoxycarbonyl-phenyl, carboxy-phenyl, nitrogen-containing heterocyclic group, lower alkyl, or lower alkyl having a substituent selected from lower alkoxycarbonyl, carboxy, lower alkoxycarbonyl-phenyl, carboxy-phenyl, lower alkoxycarbonyl-cycloalkyl and carboxy-cycloalkyl, or a pharmaceutically acceptable salt thereof, which are useful as a platelet aggregation-inhibiting agent and as an agent for the treatment, amelioration and/or prophylaxis of a variety of thrombosis or embolism, coronary and cerebral vascular smooth muscle vellication, asthma, and the like, processes for the preparation thereof, and pharmaceutical composition containing said compound as an active ingredient.