In a walking assistance device (10) including a main frame (22) supporting a power generator (26, 28) and worn on a pelvic part of a user, the main frame is provided with an opening (23) in a middle part thereof, and an electronic unit (25) is received in the opening. As the electronic unit is placed in the middle part of the main frame which is relatively free from deformation, the electronic unit is protected from deformation or stress that could impair the reliability of the electronic unit. To achieve both an easy access to the electronic unit, and an attractive appearance, the opening may be provided with a lid (24) that selectively closes the opening from a side adjacent to the user, and the lid may be formed as a back support member for supporting a back part of the user. As the lid serves the dual purposes, the weight and cost of the device can be minimized. For the convenience of the handling of the lid, the lid may be supported by the main frame via a hinge (121) provided adjacent to an upper or lower part of the opening.
