By Elisabeth O'Leary and Emma Pinedo

MADRID (Reuters) - Spain's Princess Cristina, daughter of King Juan Carlos, was charged on Wednesday with being an accomplice in an embezzlement case against her husband, the latest high-level graft investigation to anger Spaniards suffering a severe recession.

Examining magistrate Jose Castro ordered the princess, 47, to appear before him on April 27 to answer charges of complicity in a pre-trial investigation that started two years ago.

It was the first time a member of the royal family had been the subject of criminal proceedings since Juan Carlos came out of exile in the 1970s to reclaim the throne after the end of the Francisco Franco dictatorship.

Castro said there was evidence the princess had aided and abetted or at least been an accomplice of her husband, Inaki Urdangarin, who has been charged with fraud, tax evasion, falsifying documents and embezzlement of 6 million euros in public funds when he headed a charitable foundation.

"The law is the same for everyone," the magistrate said in a court document explaining his decision, echoing the king's own words in his 2011 Christmas address to the nation.

Disenchantment with the rich and powerful has grown in Spain as unemployment has soared to 26 percent, one of the worst rates in Europe, and an increasing number of well-known politicians have been named in corruption investigations.

Corruption experts said Castro was preparing to commit Urdangarin and Cristina to standing trial. The pre-trial investigation is expected to end in a few months and would be followed by a waiting period of several months before a trial.

The royal family was surprised by Castro's ruling since he had earlier indicated he would not charge Cristina, a spokesman told Reuters. However, the spokesman said, the royal family had "maximum respect" for judicial decisions.

Manuel Villoria, an expert in corruption and professor of political science at King Juan Carlos University, called the charges "devastating" for the royal family.

"He is saying he considers (Cristina) an accomplice, that he (Urdangarin) could not have done it without her. She had knowledge and didn't put a stop to it," Villoria said.

The decision is likely to deepen public dissatisfaction with the royal family and fuel debate on whether the once-popular king should abdicate in favor of his son, Crown Prince Felipe.

SCANDAL REACHES GOVERNING PARTY OFFICIALS

Castro had been looking into emails which were sent by Urdangarin to his wife asking for her advice on business matters at his charitable Noos Foundation.

A former Olympic handball player, Urdangarin is accused of using his connections to win public contracts to stage events on the Mediterranean island of Mallorca and elsewhere in Spain. Urdangarin has denied any wrongdoing.

In an unrelated case that has also stirred public ire, judges have brought charges against three former treasurers of the governing People's Party for crimes ranging from bribery to money laundering and tax evasion.

King Juan Carlos, 75, and his wife, Queen Sofia, have tried to distance themselves from the corruption scandal. Urdangarin has been barred from royal family events, and photographs of him have been taken off the official website.

"I think this is a good thing. If she did something wrong, it's logical that justice be done," said Diana Presa, a student in Madrid.

But unhappiness with the king himself has increased as a once-respectful media have devoted much coverage to his luxury lifestyle, rumors of adultery and allegations of graft in the royal family while many Spaniards struggle with recession.

Juan Carlos was once revered for his role in shepherding Spain's transition to democracy after Franco's death in 1975, but his reputation has since deteriorated.

Last year he broke a hip while hunting elephants on safari in Africa, revealing a lavish pastime that offended Spaniards grappling with a steep fall in their standard of living.

In December a survey found 79 percent of Spaniards felt that Prince Felipe was ready to be head of state, while the king's personal approval rating had fallen to 58 percent from 74 percent registered before his safari.

The latest CIS poll showed Spaniards naming corruption as the country's second biggest problem after unemployment.

(Additional reporting by Inmaculada Sanz, Editing by Fiona Ortiz and Mark Heinrich)