A wearable device for obtaining bio information comprising: a first electrode portion comprising a current electrode and a voltage electrode which are arranged to contact a first body portion of a user of the wearable device; a second electrode portion comprising a current electrode and a voltage electrode which are sized and arranged to be simultaneously touchable by a finger of the user; and a measuring unit configured to measure a bio impedance of the user by applying a current to the current electrodes of the first and second electrode portions and detecting a voltage at the voltage electrodes of the first and second electrode portions, wherein, when the first electrode portion and the second electrode portion are touched by the user, the first electrode portion and the second electrode portion form a circuit configuration through the user via which the measuring unit measures the bio impedance, the wearable device is a wrist-wearable type and comprises a main body and a strap, the first electrode portion is arranged on an inner surface of the main body or an inner surface of the strap so as to contact a wrist of the user, and the second electrode portion is arranged on an outer surface of the main body or an outer surface of the strap, characterised in that: for at least one of the first electrode portion and the second electrode portion, the current electrode of said portion has an area different from the area of the voltage electrode of said portion, and a first electrode of the two electrodes of the second electrode portion surrounds a second electrode of the two electrodes of the second portion. a first electrode portion comprising a current electrode and a voltage electrode which are arranged to contact a first body portion of a user of the wearable device; a second electrode portion comprising a current electrode and a voltage electrode which are sized and arranged to be simultaneously touchable by a finger of the user; and a measuring unit configured to measure a bio impedance of the user by applying a current to the current electrodes of the first and second electrode portions and detecting a voltage at the voltage electrodes of the first and second electrode portions, wherein, when the first electrode portion and the second electrode portion are touched by the user, the first electrode portion and the second electrode portion form a circuit configuration through the user via which the measuring unit measures the bio impedance, the wearable device is a wrist-wearable type and comprises a main body and a strap, the first electrode portion is arranged on an inner surface of the main body or an inner surface of the strap so as to contact a wrist of the user, and the second electrode portion is arranged on an outer surface of the main body or an outer surface of the strap, characterised in that: for at least one of the first electrode portion and the second electrode portion, the current electrode of said portion has an area different from the area of the voltage electrode of said portion, and a first electrode of the two electrodes of the second electrode portion surrounds a second electrode of the two electrodes of the second portion.