Abstract: The present invention provides a method for introducing a gene into Euglena, which can stably maintain a foreign gene, and a transformant therefrom. In this method of introducing a gene into Euglena, a DNA fragment containing an amino acid sequence for encoding a protein is introduced into a Euglena cell. The method includes a step of producing a binary vector containing a DNA fragment, a step of obtaining a linear gene fragment that includes a T-DNA region including the DNA fragment in the binary vector, and a direct gene introduction step of directly introducing the linear gene fragment into the Euglena cell.