A precursor for chemical vapor deposition (CVD), which is a precursor for producing an indium oxide thin film by chemical vapor deposition, can be stored for a long period, and is easy to handle upon use when chemical vapor deposition is carried out; and a method for storing the precursor. A precursor for chemical vapor deposition, characterized by containing an alkylcyclopentadienylindium (I) (C5H4R1—In) as a main component, also containing at least one component selected from alkylcyclopentediene (C5H5R2), dialkylcyclopentadiene ((C5H5R3)2), trisalkylcyclopentadienylindium (III) ((C5H4R4)3—In) and triscyclopentadienyl indium (III) as secondary components (wherein R1 to R4 independently represent an alkyl group having 1 to 4 carbon atoms), and containing substantially no solvents.