Investor Offering Diddy $30 Million For House Says It Isn't Worth $60 Million

Diddy's house is underwhelming when you walk in and defintely not worth $60 million ... this according to the investor who says he's offering half the asking price.

We caught up with Bo Belmont -- founder and owner of real estate company Belwood Investments -- out in Los Angeles Friday ... and, we had to ask him about putting in a $30 million offer for the rapper's Holmby Hills mansion.

First off, Belmont says this is a real offer ... telling us his company has emailed the listing agent for the property -- though they haven't heard back yet.

Belmont says his company offered $30 million -- well under Diddy's asking price of $62 million -- because when he saw the property he was underwhelmed ... feeling it didn't meet his $60 million expectation.

As for whether Diddy will accept an offer so much lower than his asking ... Bo says he might -- after all, his company was able to purchase Kanye West's gutted Malibu mansion for nearly $40 million less than Ye originally wanted.

Bo plans to stick to his guns in any negotiation with Diddy, he tells us ... 'cause if Diddy wants more and comes back with a counter, his plan is to offer $27.5 million -- taking money off the table instead of piling more on it.

Worth noting ... Bo's fine with all of the alleged activities that may have gone down in the house -- explaining he plans to completely redesign the interior so it looks and feels nothing like the current mansion.

We've spoken to other realtors in the past about Diddy's mansion BTW ... and, they say two of the big issues with selling the property are the asking price and the stigma -- so sounds like Belmont's keeping both in mind.