The main attraction of the temple is the unique idol of Lord Shiva, two Sivalinga on the same pedestal and he is worshipped here as Erattayappan. The Sanctum Sanctorum is noted for its intricate carvings. Vattezhuthu and Malayalam inscriptions have been engraved on the walls of the temple and the temple is also known as Perumtrikkovil.

The shrikovil is on the first floor and the roof over the second floor runs the entire length of the building, which is a rarity in Kerala style of architecture. The whole edifice is 21 m high and stands apart from the nalambalam. The nalambalam, built in wood, is designed in the vimana style of stone construction and is decorated by thousands of oil lamps. These lamps are lit during festive occasions. The octagonal shikhara on top blends with the gabled roof, giving it a magnificent appearance.

The Mahadev temple is famous for Peruvanam Pooram. This annual festival of the temple is a one-day celebration. In the evening, elephant processions, from the neighboring temples, reach the Mahadev temple and pays tribute to Lord Shiva. It is followed by the display of thirty traditionally ornamented elephants. To add to the beauty of the festival, the traditional percussion music, Pancharimelam and Pandimelam, are also performed by the drummers.