Crystal growth apparatus

A crystal growth apparatus comprising:

• a heat source;
• a crucible including a container body in which a raw material is to be received and a lid part on which a seed crystal is to be mounted;
• a first heat insulating part which is disposed externally of the crucible and in which at least one first through-hole penetrating in a thickness direction is provided;
• a second heat insulating part which is disposed externally of the first heat insulating part and in which at least one second through-hole penetrating in a thickness direction is provided;
• a moving mechanism configured to move the first heat insulating part and the second heat insulating part relative to each other, and to switch between a state in which the first through-hole and the second through-hole communicate with each other and a state in which the first and second through holes do not communicate with each other;
• and
• a radiation type temperature measuring unit configured to measure a temperature of the crucible via the first through-hole and the second through-hole,
• wherein the first heat insulating part covers an upper surface of the crucible and an outer surface of the crucible from a lower end of the outer surface of the crucible to an upper end of the outer surface of the crucible.