A lower back assistance apparatus including: a back frame 14 mounted to the back of a user and capable of movement following a user tilting forward shoulder straps 22 that are attached to a back mounting section and extend towards the user trunk forward side for supporting the trunk of a user from the forward side thigh plates 18 for mounting to the front of lower limbs of the user coupling frames 20 with one end coupled to the thigh plates 18 and the other end coupled to the back frame 14 by joint sections 16 so as to allow relative movement with respect to the back frame 14, and capable of maintaining a non-bent profile during the relative movement and actuators 40 that in an actuated state prevent the back frame 14 from tilting in the user forward direction.