A stimulation device includes a rotary member, a fixing member, a sliding member and a swinging unit. The rotary member defines a first groove therein, wherein the first groove is annular and non-circular. The fixing member defines a second groove therein, wherein the second groove is linear-shaped. The sliding member includes a first sliding portion being slidably engaged into the first groove and a second sliding portion being slidably engaged into the second groove. The swinging unit includes at least one swinging bar being rotatably connected to the sliding member.