A solar cell module (10, 18), comprising: a substrate which comprises a first surface receiving a light and a second surface at a back side of the first surface; a first electrode provided on the first surface of the substrate; and a second electrode provided on the second surface of the substrate and comprising an elongated second output extraction portion, wherein the second output extraction portion comprises a first opening below the first electrode, wherein a part of a periphery of the first electrode is disposed in an orthogonal projection of the first electrode on a plane parallel to the second surface in the first opening, and wherein the first electrode comprises an elongated first output extraction portion, the solar cell module (10, 18) further comprising a first inner lead formed to be elongated and connected to the first output extraction portion along a longitudinal direction of the first output extraction portion, and a second inner lead formed to be elongated and connected to the second output extraction portion along a longitudinal direction of the second output extraction portion, wherein the first opening has a width greater than a width of the first output extraction portion in a lateral direction of the first output extraction portion, wherein the second electrode comprises a power collection unit formed on the almost entire surface of the second surface of the substrate except in a portion defining a second opening at a back side of the first output extraction portion, wherein the second output extraction portion is formed on and overlapping a part of the second power collection unit, wherein the second opening is located in a part where the second output extraction portion is located, wherein a width of the second opening is greater than the width of the first output extraction portion, and wherein a width of the first opening is greater than a width of the second inner lead. a substrate which comprises a first surface receiving a light and a second surface at a back side of the first surface; a first electrode provided on the first surface of the substrate; and a second electrode provided on the second surface of the substrate and comprising an elongated second output extraction portion, wherein the second output extraction portion comprises a first opening below the first electrode, wherein a part of a periphery of the first electrode is disposed in an orthogonal projection of the first electrode on a plane parallel to the second surface in the first opening, and wherein the first electrode comprises an elongated first output extraction portion, the solar cell module (10, 18) further comprising a first inner lead formed to be elongated and connected to the first output extraction portion along a longitudinal direction of the first output extraction portion, and a second inner lead formed to be elongated and connected to the second output extraction portion along a longitudinal direction of the second output extraction portion, wherein the first opening has a width greater than a width of the first output extraction portion in a lateral direction of the first output extraction portion, wherein the second electrode comprises a power collection unit formed on the almost entire surface of the second surface of the substrate except in a portion defining a second opening at a back side of the first output extraction portion, wherein the second output extraction portion is formed on and overlapping a part of the second power collection unit, wherein the second opening is located in a part where the second output extraction portion is located, wherein a width of the second opening is greater than the width of the first output extraction portion, and wherein a width of the first opening is greater than a width of the second inner lead.