PROBLEM TO BE SOLVED: To provide a lock mechanism that improves safety of a wheelchair user, and takes comfortableness of the user into consideration as well.SOLUTION: A lock mechanism for locking the rotation of main wheels 11 of a wheelchair 10 includes a sensor 16 for detecting that a wheelchair user is seated in the wheelchair 10, a lock part 100 configured so as to lock or unlock the rotation of the main wheels 11 by the drive of an actuator 19, and a control part 100 electrically connected to the sensor 16 and the lock part 100 for controlling the operation of the actuator 100 on the basis of the signal of the sensor 16. When the sensor 16 does not detect that the wheelchair user is seated in the wheelchair 10, the state that the main wheels 11 are locked by the lock part 100 is maintained, and when the sensor 16 detects that the wheelchair user is seated in the wheelchair 10, the lock part 100 unlocks the main wheels 11.SELECTED DRAWING: Figure 1
