A method of recovering a decomposition product of a thermosetting resin cured product, the method includes a step of contacting an object to be treated, that contains a thermosetting resin cured product, with a treatment liquid containing an alkali metal compound and an alcohol solvent, to decompose and dissolve the thermosetting resin cured product; a step of mixing the treatment liquid, in which a decomposition product of the thermosetting resin cured product is dissolved, and an acidic aqueous solution to separate the mixture into an aqueous layer and an organic layer containing the decomposition product; and a step of recovering the organic layer.