Terrence Howard owes his ex-wife $508,000 and counting ... so she claims, and she's gunning for a payday.

Michelle Ghent claims Terrence has been hiding assets and grossly undervaluing what he makes a month to avoid his spousal support obligations.

TMZ broke the story ... Terrence is required to pay Michelle $5,800 a month in spousal support, but if he makes more than $62,500 a quarter, she gets 21% of the excess. According to her docs, Terrence made $125,000 an episode in Season 1 and he's sure to get a huge raise.

Michelle claims Terrence has not only failed to pay the 21%, but she says he's way behind in the $5,800 monthly obligation ... to the tune of more than $100k.

Also according to Michelle's docs, Terrence is using his first ex-wife's business to divert his earnings, making it appear he earns very little. In fact, Terrence claimed as recently as November all he was getting in the way of income was just shy of $6k a month ... money that was paid by the ex-wife's business.

"Empire" started shooting in September, so that's when the bucks started rolling in.

But all good things come to an end, and according to the divorce, Michelle's spousal support ends next year

Read more: http://www.tmz.com/2015/03/31/terrence-howard-ex-wife-money-empire-salary-owes-spousal-support/#ixzz3Vyl3jcgT