An electric hub unit comprising: a hub being a hollow hub and composed of first casing and a second casing, an electric unit located between the first and second casings (11, 12), an axle extending through two respective centers of the first and second casings (11, 12), the first casing having a reception recess defined in one side thereof and multiple notches defined in an inner periphery of the reception recess, a first extension and a second extension extending axially from the first casing and toward in opposite directions, characterized by the fact that it further comprises: a bearing located in an inside of the second extension; a socket unit having a tubular portion which has a stepped portion extending radially from outside of the tubular portion; a ratchet unit having a base and a ratchet ring, the base located to the stepped portion and having multiple pawls, the ratchet ring having multiple teeth which are located corresponding to the notches, the ratchet ring having multiple ratchet teeth defined in an inner periphery thereof, the ratchet ring located in the reception recess, the teeth engaged with the notches, the socket unit mounted to outside of the first casing and mounted to the axle, the pawls engaged with the ratchet teeth, a bearing and a plate located between the stepped portion of the tubular portion and the first extension. a hub being a hollow hub and composed of first casing and a second casing, an electric unit located between the first and second casings (11, 12), an axle extending through two respective centers of the first and second casings (11, 12), the first casing having a reception recess defined in one side thereof and multiple notches defined in an inner periphery of the reception recess, a first extension and a second extension extending axially from the first casing and toward in opposite directions, characterized by the fact that it further comprises: a bearing located in an inside of the second extension; a socket unit having a tubular portion which has a stepped portion extending radially from outside of the tubular portion; a ratchet unit having a base and a ratchet ring, the base located to the stepped portion and having multiple pawls, the ratchet ring having multiple teeth which are located corresponding to the notches, the ratchet ring having multiple ratchet teeth defined in an inner periphery thereof, the ratchet ring located in the reception recess, the teeth engaged with the notches, the socket unit mounted to outside of the first casing and mounted to the axle, the pawls engaged with the ratchet teeth, a bearing and a plate located between the stepped portion of the tubular portion and the first extension. a bearing located in an inside of the second extension; a socket unit having a tubular portion which has a stepped portion extending radially from outside of the tubular portion; a ratchet unit having a base and a ratchet ring, the base located to the stepped portion and having multiple pawls, the ratchet ring having multiple teeth which are located corresponding to the notches, the ratchet ring having multiple ratchet teeth defined in an inner periphery thereof, the ratchet ring located in the reception recess, the teeth engaged with the notches, the socket unit mounted to outside of the first casing and mounted to the axle, the pawls engaged with the ratchet teeth, a bearing and a plate located between the stepped portion of the tubular portion and the first extension.