A crystal oscillator and an oscillating device are provided. The crystal oscillator includes a resonator, a low-thermal conductivity glue, an integrated circuit chip, and a heating element. In the resonator, a crystal blank is hermetically encapsulated. The low-thermal conductivity glue wraps the resonator to suppress temperature variation in the resonator. The integrated circuit chip is disposed below the resonator, and the heating element is configured to supply heat to the resonator.