UPDATE 1-Mitsui Fudosan quarterly profit up 32 pct

* Reports 32 pct rise in April-June operating profit

* Solid apartment sales, shopping complex contributed to sales

* Keeps annual profit outlook unchanged (Adds details)

TOKYO, July 30 (Reuters) - Mitsui Fudosan Co (8801.T), Japan's largest developer, reported a 32 percent rise in quarterly profit helped by a solid performance in apartment sales and by its lease business.

In common with other property developers, Mitsui Fudosan has been struggling to reduce the number of unsold apartments as Japan's recession saps demand for new homes.

But the developer managed to increase profits with the completion of some large apartment buildings, and as office and shopping complexes generated solid revenues.

In the three months to June, Mitsui Fudosan's operating profit rose to 35.6 billion yen ($375.1 million), with revenues up 10 percent at 311.5 billion yen.

Mitsui Fudosan, the world's No.4 developer by market capital, said unsold houses and apartments rose to 1,058 units as of June, up from 919 in March. But profits from the residential sector more than doubled after it launched sales of big apartment buildings.

Citing strong apartment sales, it said it has already achieved about 50 percent of its annual sales target of 5,400 units.

Tokyo-based Mitsui Fudosan also saw its rental revenues rise, buoyed by the opening of a Lalaport shopping mall in Shizuoka prefecture near Tokyo and Aoyama OM-Square office building in central Tokyo.

But the average vacancy rate of Mitsui Fudosan-owned office and commercial buildings rose to 2.7 percent from 2.2 percent in March, it said.

For the full business year to March 2010, Mitsui Fudosan stuck to its operating profit forecast of 150 billion yen, slightly above a consensus estimate for a 140 billion yen profit in a survey of 16 analysts polled by by Thomson Reuters.

Shares of Mitsui Fudosan closed unchanged at 1,657 yen before the announcement. The shares have fallen about 31 percent in the past 12 months, underperforming a 24.5 percent decline in the benchmark Nikkei 225 average .N225. ($1=94.91 Yen) (Reporting by Mariko Katsumura; Editing by Michael Watson)