A method for manufacturing dialkylaluminum monohalide is provided by which dialkylaluminum monohalide substantially including no zinc component after recovering dialkylzinc from a reaction product obtained by a reaction of zinc halide and trialkylaluminum used as raw materials can be efficiently obtained on an industrial scale at a high yield. According to the method for manufacturing dialkylaluminum monohalide of the present invention, zinc halide is reacted with trialkylaluminum to produce dialkylzinc and dialkylaluminum monohalide, and after the dialkylzinc is separated from a reaction product by distillation, metal aluminum in which a molar ratio is 0.40 or more to zinc component, that is dissolved in the reaction product, and then the mixture is distilled to separate the dialkylaluminum monohalide which substantially includes no zinc component.