The present invention provides an anti-PD-L1 antibody capable of repeated administration even to animals other than rat. An anti-PD-L1 antibody comprising (a) a light chain comprising a light chain variable region containing CDR1 having the amino acid sequence of QSLLYSENQKDY (SEQ ID NO: 37), CDR2 having the amino acid sequence of WAT and CDR3 having the amino acid sequence of GQYLVYPFT (SEQ ID NO: 38) and the light chain constant region of an antibody of an animal other than rat; and (b) a heavy chain comprising a heavy chain variable region containing CDR1 having the amino acid sequence of GYTFTSNF (SEQ ID NO: 39), CDR2 having the amino acid sequence of IYPEYGNT (SEQ ID NO: 40) and CDR3 having the amino acid sequence of ASEEAVISLVY (SEQ ID NO: 41) and the heavy chain constant region of an antibody of an animal other than rat. A pharmaceutical composition comprising the above anti-PD-L1 antibody as an active ingredient. A method for preparing the above anti-PD-L1 antibody is also provided.