An anti-Notch4 antibody or a Notch4 binding fragment thereof, wherein said antibody or a Notch4 binding fragment thereof comprises heavy and light chains and is selected from any of the following (i) - (vii) : (i) an antibody in which the variable region of said heavy chain comprises the amino acid sequence of SEQ ID NO. 33 and the variable region of said light chain comprises the amino acid sequence of SEQ ID NO. 45, (ii) an antibody in which the variable region of said heavy chain comprises the amino acid sequence of SEQ ID NO. 35 and the variable region of said light chain comprises the amino acid sequence of SEQ ID NO. 45, (iii) an antibody in which the variable region of said heavy chain comprises the amino acid sequence of SEQ ID NO. 33 and the variable region of said light chain comprises the amino acid sequence of SEQ ID NO. 47, (iv) an antibody in which the variable region of said heavy chain comprises the amino acid sequence of SEQ ID NO. 35 and the variable region of said light chain comprises the amino acid sequence of SEQ ID NO. 49, (v) an antibody in which the variable region of said heavy chain comprises the amino acid sequence of SEQ ID NO. 33 and the variable region of said light chain comprises the amino acid sequence of SEQ ID NO. 51, (vi) an antibody in which the variable region of said heavy chain comprises the amino acid sequence of SEQ ID NO. 39 and the variable region of said light chain comprises the amino acid sequence of SEQ ID NO. 45, and (vii) an antibody in which the variable region of said heavy chain comprises the amino acid sequence of SEQ ID NO. 35 and the variable region of said light chain comprises the amino acid sequence of SEQ ID NO. 47. (i) an antibody in which the variable region of said heavy chain comprises the amino acid sequence of SEQ ID NO. 33 and the variable region of said light chain comprises the amino acid sequence of SEQ ID NO. 45, (ii) an antibody in which the variable region of said heavy chain comprises the amino acid sequence of SEQ ID NO. 35 and the variable region of said light chain comprises the amino acid sequence of SEQ ID NO. 45, (iii) an antibody in which the variable region of said heavy chain comprises the amino acid sequence of SEQ ID NO. 33 and the variable region of said light chain comprises the amino acid sequence of SEQ ID NO. 47, (iv) an antibody in which the variable region of said heavy chain comprises the amino acid sequence of SEQ ID NO. 35 and the variable region of said light chain comprises the amino acid sequence of SEQ ID NO. 49, (v) an antibody in which the variable region of said heavy chain comprises the amino acid sequence of SEQ ID NO. 33 and the variable region of said light chain comprises the amino acid sequence of SEQ ID NO. 51, (vi) an antibody in which the variable region of said heavy chain comprises the amino acid sequence of SEQ ID NO. 39 and the variable region of said light chain comprises the amino acid sequence of SEQ ID NO. 45, and (vii) an antibody in which the variable region of said heavy chain comprises the amino acid sequence of SEQ ID NO. 35 and the variable region of said light chain comprises the amino acid sequence of SEQ ID NO. 47. <EOS>