a polyester is a polycondensation product of a diol component and a dicarboxylic acid component . in this polyester , the diol component includes a tricyclodecanediol of following formula : wherein n is 0 or a positive integer , and carbon atoms constituting a ring may each have a substituent , or the dicarboxylic acid component includes a tricyclodecanedicarboxylic acid of following formula : wherein m is 0 or a positive integer , and carbon atoms constituting a ring may each have a substituent . the polyester has high heat resistance , low water absorbency , excellent optical characteristics and satisfactory moldability .