Neighbours to the proposed butterfly haven in Llanteg, Pembrokeshire, had objected to the proposal for the year-round visitor attraction featuring moths, butterfly, birds and insects.
The approved centre will be built in phases over seven to 10 years.
The proposal said it had the potential to bring 25,000 visitors a year.
The centre will have conservation biomes, a cafe, education centre, birdhouses, ponds and landscaping, along with car parking, according to the Local Democracy Reporting Service.
Four biomes – for European, South American, South East Asian and African species – would be built on the rough pasture land, wildlife gardens, ponds and nature reserve areas linked into existing wildlife corridors.
Planning agent Andrew Vaughan-Harries told Pembrokeshire planners that applicant Kevin Caley, a zoologist and marine biologist, was a “passionate man when it comes to moths and butterflies”.
A “small scale” visitor centre would help fund the project and create 10 jobs, with conservation a key element, the agent added.
Neighbour Malcolm Thomas told the committee of his concerns about highway safety and the impact on his access with increased visitors.
Councillors David Pugh and Vic Dennis agreed but the committee said conditions linked to the application would be sufficient to mitigate problems.
There were 17 letters of support and two against the proposed development.
Delegated power was granted for the interim head of planning to permit the application following the resolution of drainage issues.