This 40-foot rooftop pool isn’t part of a hotel, but a tenants’ amenity at The Ellery, a west midtown luxury rental apartment project.

The building by Taconic Partners and National Real Estate Advisors has an address of 312 W. 43rd St. but its taller portion is a 32-story tower above West 42nd Street.

Leasing began last week for 330 studio, one- and two-bedroom units to open this year.

Features also include a fitness center, full-service spa and a garden between the towers.

There are 41,500 square feet of retail space on both sides.