Polyester resin, coating agent, adhesive, resin composition, ink, and method for producing polyester resin

A polyester resin comprising:

• a constitutional unit A derived from a carboxylic acid having a cyclic structure and containing 5 or more carboxyl groups;
• a constitutional unit derived from a dicarboxylic acid;
• and
• a constitutional unit derived from a polyhydric alcohol,
• wherein
• the constitutional unit A has a content of 0.01 parts by mole or more and 5 parts by mole or less with respect to 100 parts by mole of the constitutional unit derived from a dicarboxylic acid,
• the carboxylic acid having a cyclic structure and containing 5 or more carboxyl groups is at least one selected from the group consisting of benzenepentacarboxylic acid, cyclohexanehexacarboxylic acid and mellitic acid,
• the acid value of the polyester resin is 0.1 mgKOH/a or more and 0.8 mgKOH/a or less, and
• the hydroxyl value of the polyester resin is 6 mgKOH/g or more and 27 mgKOH/g or less.