A rotary switch includes a base forming a number of contacts, a support apparatus installed in the base, and a rotary apparatus rotatably installed in the support apparatus. The support apparatus forms zigzag first and second guiding portions. The rotary apparatus includes a rotary pole, a trigger mounted to the rotary pole, two abutting poles, and two resilient members respectively connected between two opposite ends of the rotary pole and the abutting poles. An end portion of each abutting pole slides along the first guiding portion, to allow the abutting poles to stretch and withdraw along a lengthwise direction of the rotary pole, and allow the abutting poles to undulate along the second guiding portion in a direction perpendicular to the lengthwise direction of the rotary pole, to allow the rotary pole to contact and trigger one of the contacts or pass over the contact.