To provide a growth promoter of strawberry fruit and a flower bud formation promoter of strawberry, capable of achieving growth promotion of strawberry fruit and flower bud formation promotion of strawberry by scattering or irrigating them to strawberry properly even without using stress cultivation or many variety.SOLUTION: There are provided a growth promoter of strawberry fruit and a flower bud formation promoter of strawberry containing an oxo fatty acid derivative having a structural formula of Formula: HOOC-(R)-C=C-C(=O)-R(I), wherein Ris a linear or branched alkyl group having 6 to 12 carbon atoms and may contain one or more double bond, and Ris an alkyl group having 2 to 8 carbon atoms and may contain one or more branched and/or double bond, or a salt thereof as an active component.SELECTED DRAWING: None
