Disclosed is a glucagon-like peptide-1 (GLP-1) analogue which is obtained by ameliorating a highly antigenic GLP-1 analogue so that the GLP-1 analogue has reduced antigenicity without being lowered in the blood glucose suppressing activity. Specifically disclosed is a glycosylated form of an antigenic GLP-1 analogue, which has GLP-1 activity and is obtained by substituting at least one amino acid of an antigenic GLP-1 analogue with a glycosylated amino acid.