A mating connector and an electrical connector for connecting an electrical circuit board and the mating connector, the electrical connector comprising: a terminal having a connecting portion to be connected to the electrical circuit board and a contact portion configured to be contacted with a terminal of the mating connector; and a housing for holding the terminal, wherein said housing includes a fixed housing to be attached to the electrical circuit board and a movable housing arranged to be movable relative to the fixed housing, said terminal includes a fixed side held portion held with the fixed housing, a movable side held portion held with the movable housing, and an elastic portion situated between the fixed side held portion and the movable side held portion, said housing includes an accommodating space situated between the fixed housing and the movable housing for accommodating the elastic portion, said terminal further includes a fixed side transition portion situated between the elastic portion and the fixed side held portion and a movable side transition portion situated between the elastic portion and the movable side held portion, and said elastic portion includes at least a first wave shape portion, said first wave shape portion having a first bent portion and a pair of first straight portions (14F, 14D), wherein the first bent portion is situated above the pair of first straight portions (14F, 14D) in a height direction of the elastic portion wherein the height direction is the direction perpendicular to a plate surface of the electrical circuit board, and said first straight portions (14F, 14D) are configured to extend away from each other with a distance in between decreasing toward the first bent portion, characterized in that said elastic portion includes further at least a second wave shape portion, the first wave shape portion and the second wave shape portion being formed in one continuous band shape; and said second wave shape portion having a second bent portion and a pair of second straight portions (14E, 14G) separated from the first straight portions (14F, 14D), wherein the second bent portion is situated above the pair of second straight portions (14E, 14G) in the height direction, and wherein said elastic portion includes a third bent portion between the first wave shape portion and the second wave portion so that the elastic portion has an M character shape, and wherein said fixed side transition portion and said movable side transition portion are situated below the third bent portion in the height direction, It wherein the terminal of the mating connector is of the female type. a terminal having a connecting portion to be connected to the electrical circuit board and a contact portion configured to be contacted with a terminal of the mating connector; and a housing for holding the terminal, wherein said housing includes a fixed housing to be attached to the electrical circuit board and a movable housing arranged to be movable relative to the fixed housing, said terminal includes a fixed side held portion held with the fixed housing, a movable side held portion held with the movable housing, and an elastic portion situated between the fixed side held portion and the movable side held portion, said housing includes an accommodating space situated between the fixed housing and the movable housing for accommodating the elastic portion, said terminal further includes a fixed side transition portion situated between the elastic portion and the fixed side held portion and a movable side transition portion situated between the elastic portion and the movable side held portion, and said elastic portion includes at least a first wave shape portion, said first wave shape portion having a first bent portion and a pair of first straight portions (14F, 14D), wherein the first bent portion is situated above the pair of first straight portions (14F, 14D) in a height direction of the elastic portion wherein the height direction is the direction perpendicular to a plate surface of the electrical circuit board, and said first straight portions (14F, 14D) are configured to extend away from each other with a distance in between decreasing toward the first bent portion, characterized in that said elastic portion includes further at least a second wave shape portion, the first wave shape portion and the second wave shape portion being formed in one continuous band shape; and said second wave shape portion having a second bent portion and a pair of second straight portions (14E, 14G) separated from the first straight portions (14F, 14D), wherein the second bent portion is situated above the pair of second straight portions (14E, 14G) in the height direction, and wherein said elastic portion includes a third bent portion between the first wave shape portion and the second wave portion so that the elastic portion has an M character shape, and wherein said fixed side transition portion and said movable side transition portion are situated below the third bent portion in the height direction, It wherein the terminal of the mating connector is of the female type.