A quick release device includes a crank having a first hole defined in one end thereof, the crank having a sixth hole opened on one lateral thereof, a fixing sleeve positioned in the first hole of the crank, a third hole opened at one end of the fixing sleeve, a fourth hole opened on the outside periphery of the fixing sleeve therethrough and corresponding to the sixth hole, the fourth hole communicating with the third hole, a quick release assembly partially received in the sixth hole, the quick release assembly having a second engaging rod, a fixing member and a rotating button, the second engaging rod received in the sixth hole, the fixing member connected to the crank and sleeved on the second engaging rod. When the user wants to release the pedal from the crank, the user just rotates the rotating button counterclockwise.