(EN) A wireless communication apparatus which establishes a multi hop network having a tree structure and which repeats startup and sleep is provided with: a network control unit that holds downstream path information which is information regarding a path to a wireless communication apparatus of lower level than the wireless communication apparatus in the tree structure and upstream path information which is information regarding a path to a wireless communication apparatus of higher level than the wireless communication apparatus in the tree structure the network control unit generating a downstream path control message for notification of the downstream path information; and a wireless transmission reception unit that commands the network control unit to update the upstream path information if after the downstream path control message is transmitted to an adjacent wireless communication apparatus of higher level than the wireless communication apparatus in the tree structure a confirmation of delivery of the downstream path control message is received from the adjacent wireless communication apparatus of higher level. Thus even when a node establishing a multi hop network is performing intermittent control communication paths can be updated.
