The Chevrolet suburban from 1947 was clearly a large SUV. (the suburban was introduced in 1935, but you could argue those models were station wagons, by 1947 they were clearly SUVs). The VW microbus - was from 1950.

The minivan didn't become popular until 1980s, while SUVs remained the domain of niches like families too large for a minivan, or those who regularly drove off road for another decade or two. However the SUV is clearly the older of the two.