An infusion fluid heating apparatus applicable to various types of infusion tube with different length dimensions includes a front-side tube fitting groove or a rear-side tube fitting groove formed on one of surfaces of a heating plate that receives an infusion tube in a first length between an inlet opening and an outlet opening open at the end surfaces of the heating plate. The groove also receives the infusion tube in a second length shorter than the first length. Therefore, the groove uses the second length for a relatively short infusion tube, capable of heating the tube appropriately and achieving high versatility. In addition, the tube fitting groove uses the first length for an infusion bag with a relatively long infusion tube, capable of heating the tube appropriately and increasing the maximum infusion fluid flow.