Due to showing a "crowned" Rampant Lion (which is a Heraldry term) holding an anchor, it seems to be a Netherlands Royal Navy uniform button. Here's a photo of a pre-World War 2 Netherlands Royal Air Force button. It shows a crowned Rampant Lion holding arrows and a sword. I know of no other country whose emblem shows a crowned Rampant Lion.
I should mention... an 1860s Denmark army officer button and post-1968 Canada army "general service" buttons show a crowned "Lion Passant"... which is another Heraldry term meaning "Lion moving past" (walking)... not a Lion rearing up on its hind legs (Rampant Lion).