Abstract: Provided is a thermostatic type crystal oscillator with short operation stabilization time and low power consumption. A thermostatic type crystal oscillator according to the present invention includes a crystal resonator including an IT-cut crystal blank, a vibration control circuit configured to control a vibration frequency of the crystal resonator, a temperature regulator configured to regulate a temperature of the crystal resonator within a set temperature range by repeating heating and cooling to the crystal resonator, a heat conducting plate configured to function as a heat absorbing plate and a heat dissipating plate for the temperature regulator, a temperature control circuit configured to control a temperature of the temperature regulator, and a housing that accommodates the crystal resonator. The housing defines a resonator accommodating space in which the crystal resonator is accommodated inside the housing.