The present invention relates to a process for producing a 2-(1-hydroxyalkyl)cycloalkanone which includes the steps of (i) continuously mixing a cycloalkanone and an alkyl aldehyde in the water and a base catalyst to form a reaction system and allow both the compounds to react with each other; (ii) continuously withdrawing a reaction mixture produced in the step (i) out of the reaction system while allowing the step (i) to proceed; and (iii) adding an additional amount of water containing the base catalyst to the reaction system to maintain a constant concentration of the base catalyst and/or a constant amount of water in the reaction system while allowing the step (ii) to proceed.