A shaft lock mechanism comprising a shaft, a support member, and a connecting member; the support member comprising a cylindrical part which encloses and elastically grips the shaft, and a base part extending in a radially outward direction from the cylindrical part. The connecting member has one end fixed at the bracket and is provided with a slit through which the base part of the support member is inserted in order for the support member to be supported without rotation during rotation of the shaft. Within the cylindrical part, a clearance is formed extending in the direction of the shaft. The clearance provides an appropriate amount of frictional resistance between the shaft and the cylindrical part.