The invention relates to an antisense nucleic acid compound which has a base sequence complementary to the sequence of at least eight consecutive bases in the base sequence of a gene coding for an endothelial cell growth factor and has the effect of inhibiting the expression of the growth factor; therapeutic and diagnostic agents to cancer, rheumatoid arthritis, diabetes, etc., both containing the above compound as the active ingredient; and a method of inhibiting the expression of an endothelial cell growth factor by using the above antisense nucleic acid compound.
