The company posted an online questionnaire on Monday for applicants to work at the store, due to open early next year in Alfafar in the eastern region of Valencia where the unemployment rate is over 28 percent.
"We have received so many applications to work for us in Ikea Valencia Alfafar that our server has collapsed," the company said in a Facebook message.
"We have temporarily closed the process until we find a solution that enables the online form to function correctly," added a spokesman for Ikea in Spain, Rodrigo Sanchez.
"We have received a total of 20,000 applications in the two days that the form has been available," for a total of 400 jobs in the store, Sanchez told news agency AFP.
He said that was four times more applications in the first two days than during any of Ikea's previous 15 store openings in Spain.
The largest ever number of applications to work at Ikea in Spain was 50,000 for its store that opened in the southern city of Jerez in 2009 — but those applications were spread over a whole month, he said.
Sanchez said the new branch would create 400 direct jobs in the store and 80 more indirect ones for workers such as security guards and cleaners, and involved an investment of €80 million ($109 million).
The online application page on Wednesday displayed an apologetic message promising to get in touch with all those who had tried to apply.
"We want to thank all of you for your interest in joining the team at Ikea Valencia Alfafar and apologize for the trouble caused."
Five years of on-off recession sparked by the collapse of a building boom in 2008 have thrown millions of Spaniards out of work. The national unemployment rate is currently close to 26 percent.
In August, Ikea attracted 28,616 applications for just 200 jobs at its new store in Pisa, Italy.