An interlayer film for laminated glass suitable to be arranged between a first lamination glass member and a second lamination glass member to obtain laminated glass, the interlayer film containing a thermoplastic resin and a plasticizer, the thermoplastic resin being a polyvinyl acetal resin, the interlayer film having an MD direction and a TD direction, the interlayer film having a first surface part at one side in a thickness direction, a second surface part at the other side in the thickness direction, and a center part between the first surface part and the second surface part, wherein the first surface part is a layer portion with a thickness of 50 μm from a surface at the one side toward the inside in the thickness direction, the second surface part is a layer portion with a thickness of 50 μm from a surface at the other side toward the inside in the thickness direction and the center part is a portion between the first surface part and the second surface part, when, in the MD direction of the interlayer film, a birefringence index of the first surface part, a birefringence index of the second surface part, and a birefringence index of the center part are defined as ΔnMDA, ΔnMDB, and ΔnMDC, respectively, ΔnMDA, ΔnMDB, and ΔnMDC each being 0.50 × 10 -3 or less, wherein the birefringence index of the first surface part, the birefringence index of the second surface part, and the birefringence index of the center part are measured with according to the method in the description, and the glass transition temperature, as measured according to the method in the description, of the interlayer film being 33°C or less or the content of the plasticizer in the interlayer film being 35 parts by weight or more relative to 100 parts by weight of the thermoplastic resin in the interlayer film. the interlayer film containing a thermoplastic resin and a plasticizer, the thermoplastic resin being a polyvinyl acetal resin, the interlayer film having an MD direction and a TD direction, the interlayer film having a first surface part at one side in a thickness direction, a second surface part at the other side in the thickness direction, and a center part between the first surface part and the second surface part, wherein the first surface part is a layer portion with a thickness of 50 μm from a surface at the one side toward the inside in the thickness direction, the second surface part is a layer portion with a thickness of 50 μm from a surface at the other side toward the inside in the thickness direction and the center part is a portion between the first surface part and the second surface part, when, in the MD direction of the interlayer film, a birefringence index of the first surface part, a birefringence index of the second surface part, and a birefringence index of the center part are defined as ΔnMDA, ΔnMDB, and ΔnMDC, respectively, ΔnMDA, ΔnMDB, and ΔnMDC each being 0.50 × 10 -3 or less, wherein the birefringence index of the first surface part, the birefringence index of the second surface part, and the birefringence index of the center part are measured with according to the method in the description, and the glass transition temperature, as measured according to the method in the description, of the interlayer film being 33°C or less or the content of the plasticizer in the interlayer film being 35 parts by weight or more relative to 100 parts by weight of the thermoplastic resin in the interlayer film.