A card edge connector 100 includes a longitudinal insulating housing 1, a set of terminals 2 set in the insulating housing 1 and a lock mechanism 5 for locking a daughter card 9. The insulating housing 1 has an elongated slot 112 and a pair of towers 12 positioned at two opposite ends thereof. The lock mechanism 5 includes a locking portion 51 locking the daughter card 9 and an operating portion 52 moving the locking mechanism 5. A depression 55 is formed at one end of the lock mechanism 5 close to the locking portion 51. The card edge connector 100 further includes a handle column 6 received in the depression 55 and extending out of the depression 55. Hence, we can operate the lock mechanism 5 easily, and at the same time, the room the card edge connector occupies can be reduced.