The box is set too far back into the wall. There are specially designed plastic shims that can be placed under the metal tab of the receptacle (between the box and the metal tab) which allow the receptacle to be screwed tight to the box but be in the plane of the wall.
They come in a strip and one tears off as many as needed for the space to be filled. Here you'd use 3 or 4. Fold them accordion style and snap them together. The slip around the screw so you don't hve to completely remove the screw. http://www.homedepot.com/p/Ideal-Spacers-25-Pack-172451L/202937111
What is the composition of the wall board/paneling? Is it flammable? The US best practice is that the box front edge should come out to the plane of the room side of the wall and then the receptacle is screwed tight to the box. The cover plate is supposed to seal well enough to starve a nascent fire of oxygen.
In addition, the opening in the paneling is too large on the top edge of the box. The result of these two deficiencies is that a nascent fire in the box could get oxygen from inside the wall cavity. If this were an adjustable position box, I would say crank it out flush with the wall and you'd be OK. (I can't see an adjustment screw, your hand is in the way, but there is probably not one.) As it is I would say you need non-flammable shims which fill the void space above, and, if necessary below, the box. Maybe strips of the paneling material, if it is non-flammable, or just gypsum board. These strips would mean the plastic shims would be unnecessary.
EDITAnother approach is to use a "box extender" or "tile extender", such as https://www.cableorganizer.com/arlington-industries/recessed-electric-box-extender.html or similar product by Carlon https://www.youtube.com/watch?v=l0GRyDJ9ufE With these you might have to use the plastic shims to support the extender.