Gibraltar's stores and supermarkets are filled with Spanish people picking up their weekly shop - including Marmite - and knick-knacks.
While the pound's 168-year low is hitting the spending power of those living and working in Gibraltar, it has enticed over many Spaniards who are cashing in on the relative strength of the euro, Mr Picardo said.
He told the Press Association: "A devalued pound is good for Gibraltarian exports, so from the point of view of the public finances of Gibraltar we are not doing badly.
"You'll see there will be a lot of products sold in Gibraltar, we see more Spaniards come into Gibraltar to buy things.
"I tend to go shopping with my family on a Saturday afternoon to the local supermarkets, and we are seeing a lot of Spanish couples coming in to buy curios in Gibraltar they might otherwise not have been interested in purchasing. Their euros go much further.
"People are coming in to buy ketchup and buy, dare I say it, Marmite and other British goods at more affordable prices because their euro goes further than it used to."
Picardo's comments will be welcomed by Brexiteers who have said the fall in the pound will help to boost exports and rebalance the economy. But the chief minister cautioned that while sterling's slump might boost sales to the Spanish, Britons and Gibraltarian pockets are being hit.
And the thousands of Spanish who cross the border every day to work in Gibraltar have also been hit by the slump, he said.
"They have taken a huge pay cut in the sense that many of them will have converted their salaries into euros every week, they will pay for their rent or mortgages in euros, they will pay for their electricity and water in euros, so they've immediately taken a pay cut," Mr Picardo said.
"Many of them may actually be purchasing their consumables in Gibraltar, so that they are paid in pounds and they purchase in pounds insofar as they can.
"Of course the price of goods in Gibraltar will soon start to go up, because those consumables which are sourced in euros will become out of stock and when new stocks are replenished those are going to be more expensive.
"And this is going to affect everyone who receives their remuneration in pounds - whether it's pensioners who live in Spain, people in the United Kingdom who travel into the rest of Europe - we are all going to notice the effect.
"It's not lost on me that there isn't much of a difference between those who in the old days used to say, 'A strong pound is a strong Britain' and those who during the Brexit campaign said we need to get out of the European Union to make Britain stronger.
"Well I think there is a huge contradiction between the reality which we face today and the arguments they made."