An ion exchange membrane comprising: a first ion exchange resin layer; and a second ion exchange resin layer and a third ion exchange resin layer respectively provided on both surfaces of the first ion exchange resin layer, a fourth ion exchange resin layer provided on a surface opposite to the surface in contact with the first ion exchange resin layer of the second ion exchange resin layer; and a fifth ion exchange resin layer provided on a surface opposite to the surface in contact with the first ion exchange resin layer of the third ion exchange resin layer, wherein the first to the fifth ion exchange resin layers (101, 102, 103, 104, 105) each include one or more types of ionomers; the ionomer included in each of the second ion exchange resin layer and the third ion exchange resin layer has a higher equivalent weight than the ionomer of the first ion exchange resin layer; and the ionomer included in each of the fourth ion exchange resin layer and the fifth ion exchange resin layer has a higher equivalent weight than the ionomers of the second ion exchange resin layer and the third ion exchange resin layer; wherein the first ion exchange resin layer includes one or more types of ionomers having an equivalent weight of greater than or equal to 500 g/mol and less than or equal to 750 g/mol; the second ion exchange resin layer and the third ion exchange resin layer each include one or more types of ionomers having an equivalent weight of greater than 750 g/mol and less than or equal to 900 g/mol; and the fourth ion exchange resin layer and the fifth ion exchange resin layer each include one or more types of ionomers having an equivalent weight of greater than 900 g/mol and less than or equal to 1,100 g/mol, wherein the equivalent weight means a weight of a polymer having 1 equivalent of sulfonic acid and is determined as follows: a polymer corresponding to 1 g is introduced to 3 M NaCl, and after stirring the result for 1 day, a 0.1 M NaOH standard solution is added until the pH becomes 7; and the equivalent weight is calculated through the following equation EW g mol = m NaOH × V NaOH × 1000 wherein *m=polymer mass=1 g, *[NaOH]=0.1 M and *VNaOH=volume of introduced NaOH. a first ion exchange resin layer; and a second ion exchange resin layer and a third ion exchange resin layer respectively provided on both surfaces of the first ion exchange resin layer, a fourth ion exchange resin layer provided on a surface opposite to the surface in contact with the first ion exchange resin layer of the second ion exchange resin layer; and a fifth ion exchange resin layer provided on a surface opposite to the surface in contact with the first ion exchange resin layer of the third ion exchange resin layer, wherein the first to the fifth ion exchange resin layers (101, 102, 103, 104, 105) each include one or more types of ionomers; the ionomer included in each of the second ion exchange resin layer and the third ion exchange resin layer has a higher equivalent weight than the ionomer of the first ion exchange resin layer; and the ionomer included in each of the fourth ion exchange resin layer and the fifth ion exchange resin layer has a higher equivalent weight than the ionomers of the second ion exchange resin layer and the third ion exchange resin layer; wherein the first ion exchange resin layer includes one or more types of ionomers having an equivalent weight of greater than or equal to 500 g/mol and less than or equal to 750 g/mol; the second ion exchange resin layer and the third ion exchange resin layer each include one or more types of ionomers having an equivalent weight of greater than 750 g/mol and less than or equal to 900 g/mol; and the fourth ion exchange resin layer and the fifth ion exchange resin layer each include one or more types of ionomers having an equivalent weight of greater than 900 g/mol and less than or equal to 1,100 g/mol, wherein the equivalent weight means a weight of a polymer having 1 equivalent of sulfonic acid and is determined as follows: a polymer corresponding to 1 g is introduced to 3 M NaCl, and after stirring the result for 1 day, a 0.1 M NaOH standard solution is added until the pH becomes 7; and the equivalent weight is calculated through the following equation EW g mol = m NaOH × V NaOH × 1000 wherein *m=polymer mass=1 g, *[NaOH]=0.1 M and *VNaOH=volume of introduced NaOH. a polymer corresponding to 1 g is introduced to 3 M NaCl, and after stirring the result for 1 day, a 0.1 M NaOH standard solution is added until the pH becomes 7; and the equivalent weight is calculated through the following equation EW g mol = m NaOH × V NaOH × 1000 wherein *m=polymer mass=1 g, *[NaOH]=0.1 M and *VNaOH=volume of introduced NaOH.