An electrode device for measuring impedances of a human body, comprising: - a housing member having an open side; - a guide rod that has first and second ends, that extends from an inner surface of the cylindrical housing member such that the first end of the guide rod is disposed at the inner surface, and that extends through the open side of the cylindrical housing member; - a cylindrical electrode member having an open end and configured to be pressed against the skin of a human body to move back and forth through the open side of the cylindrical housing member along the guide rod; the cylindrical electrode member being disposed around the guide rod and the cylindrical electrode member having a protruding portion formed at the open end thereof that allows the cylindrical electrode member to engage with the cylindrical housing member; and - a spring surrounding the guide rod and interposed between the top of the cylindrical electrode member and the top of the cylindrical housing member to resiliently move the cylindrical electrode member back and forth along the guide rod, the electrode device characterised in that: - the housing member is a cylindrical housing member - the spring abuts against the protruding portion at the open end of the cylindrical electrode member - a first housing protruding portion is formed at the open side of said cylindrical housing member such that engagement between the cylindrical electrode member and said cylindrical housing member is facilitated, and - a second housing protruding portion is formed at an other side of said cylindrical housing member such that engagement between said cylindrical housing member and a base plate is facilitated. - a housing member having an open side; - a guide rod that has first and second ends, that extends from an inner surface of the cylindrical housing member such that the first end of the guide rod is disposed at the inner surface, and that extends through the open side of the cylindrical housing member; - a cylindrical electrode member having an open end and configured to be pressed against the skin of a human body to move back and forth through the open side of the cylindrical housing member along the guide rod; the cylindrical electrode member being disposed around the guide rod and the cylindrical electrode member having a protruding portion formed at the open end thereof that allows the cylindrical electrode member to engage with the cylindrical housing member; and - a spring surrounding the guide rod and interposed between the top of the cylindrical electrode member and the top of the cylindrical housing member to resiliently move the cylindrical electrode member back and forth along the guide rod, the electrode device characterised in that: - the housing member is a cylindrical housing member - the spring abuts against the protruding portion at the open end of the cylindrical electrode member - a first housing protruding portion is formed at the open side of said cylindrical housing member such that engagement between the cylindrical electrode member and said cylindrical housing member is facilitated, and - a second housing protruding portion is formed at an other side of said cylindrical housing member such that engagement between said cylindrical housing member and a base plate is facilitated. - the housing member is a cylindrical housing member - the spring abuts against the protruding portion at the open end of the cylindrical electrode member - a first housing protruding portion is formed at the open side of said cylindrical housing member such that engagement between the cylindrical electrode member and said cylindrical housing member is facilitated, and - a second housing protruding portion is formed at an other side of said cylindrical housing member such that engagement between said cylindrical housing member and a base plate is facilitated.