To provide a movable defense apparatus capable of inhibiting entering of rainwater to some degree as well as entering of a mob, a recklessly driven car and the like without especially requiring the power for driving a relatively weighty defense wall and the installation space.

This movable defense apparatus is formed by a defense wall 2 provided near an entrance O.I of a lot G of a house, an institution and the like to prevent illegal things such as a mob, a recklessly driven car and rainwater from entering the inside of the lot G, and piston cylinder units 20, 20 for driving the defense wall 2 from a machinery room (M.R) in the underground to an upper designated position along guide devices 10, 10. Service water 30, 31 is supplied to the piston cylinder units 20, 20.