An adjusting apparatus is provided for a projector and received in a case of the projector. The case includes a front wall defining a through hole. Two protrusions each defining a notch are formed on the inside surface of the front wall. The adjusting apparatus includes two supporting members partially received in the case and movably coupled to the case, and an operating member partially exposed out of the through hole of the front wall of the case. A connecting member is connected to the operating member, and received in the notches. Each supporting member forms a plurality of teeth thereon. The connecting member forms a plurality of teeth at two ends thereof respectively for mating with the teeth of the supporting member. The operating member is rotated for driving the connecting member to move up and down relative to the supporting member.