To heighten the stability of date advancing movements in a calendar mechanism of a timepiece especially in a month-end non-correction mechanism.

A date advancing click 14, which has been formed in a minimum length required for date advancing movements, is formed long so as to advance two dates on the thirtieth day in an even month i.e. advance a toothed wheel part 10 by two teeth and heighten engageability at date advancing movements with the toothed wheel part 10 provided for a date indicator. The date advancing click 14 is deflected and restricted by a date advancement restricting member 15 so as not to be in unnecessary contact with the toothed wheel part 10 after date advancing movements.