Del Bosque believes hosts Brazil should be regarded as favourites but that the tournament will be the most testing ever, so strong is the competition.
Spain and Brazil are both among the eight top seeds who will be kept apart in the draw, but there are some weighty opponents among the unseeded pots - not least 2010's losing finalists Holland and 2006 champions Italy.
Del Bosque, in comments reported on Football Espana, said: "Brazil, as host nation, are perhaps the strongest but we shouldn't underestimate any of the African teams, particularly Ivory Coast, Ghana and Cameroon.
"Some people say that we are favourites, but we have gone from what was a disappointing past to a state of exaggerated optimism.
"We now have six months to prepare and aim to do that in the best possible way, while I hope we don't get any bad luck and find ourselves in a complicated group."
One change to the expected draw procedure has seen FIFA decide that one of the nine unseeded European teams will be put into the pot containing the unseeded South American and African countries. That European team will then be guaranteed to face a seeded South American side.
In the worst case scenario that could see a 'group of death' containing Brazil, Holland, the United States and Italy.
It had been expected that France, as the lowest-ranked European team, would be put into the second pot but FIFA has decided to draw it from all nine countries from pot four.
The decision has sparked some controversy, but Italy coach Cesare Prandelli backed the move and said he only feared being told that the Azzurri had been handed an easy draw.
He told Gazzetta dello Sport: "I don't see anything scandalous going on. I see a rule that should be modified but perhaps they should have done it sooner and not right before the draw.
"We're not afraid to face the big teams. We're prepared and hope to do well. The only thing I fear is hearing that we've ended up in an easy group, and that we're already in the quarter-finals and semi-finals. And if it turns out we have to face big teams then I'm not afraid at all. We'll play to the very end to make it through."
Pot 1 (top seeds): Brazil, Argentina, Colombia, Uruguay, Spain, Germany, Belgium and Switzerland.
Pot 2 (South America and Africa): Algeria, Cameroon, Chile, Ivory Coast, Ecuador, Ghana and Nigeria (plus one from Pot 4)
Pot 3 (North and Central America plus Asia): Australia, Costa Rica, Honduras, Iran, Japan, South Korea, Mexico, United States
Pot 4 (Europe): Bosnia-Herzegovina, Croatia, England, France, Greece, Italy, Holland, Portugal, Russia (one to go to Pot 2).