To provide a concrete curing rust prevention mold releasing agent and a curing method making use thereof capable of preventing the generation of rust in a boundary surface between a metal-made form and a concrete after water has been sprinkled as countermeasures against a crack in the concrete when base concrete is cured.

The residual part of the concrete curing rust prevention mold releasing agent is constituted of base oil within a range of 0.2 to 20 wt. % of an additional volume of a main composition using a mold releasing additive as single or together with something else and within a range of not more than 0.2 to 10 wt. % of an additional volume of an auxiliary composition using an auxiliary additive as single or together with something else. The concrete curing rust prevention mold releasing agent is adhered to a site coming into contact with water by sprinkling water among metal-made forms used for a water sprinkling function attached curing protection device, and the concrete C is placed to be cured.