Patent ID: 8149068

Claim:
A temperature controlled crystal oscillator provided with a circuit substrate having a crystal resonator, an oscillating circuit, and a temperature control circuit, arranged on one or both principal surfaces, and a container main body that accommodates said circuit substrate and has mount terminals on an outer bottom surface thereof, wherein said temperature control circuit includes at least a first temperature sensor that detects an operating temperature of said crystal resonator, a second temperature sensor that detects a surrounding temperature of said container main body, wherein a metal film surrounds a periphery of said second temperature sensor, and a heating resistor that applies heat to said crystal resonator according to a temperatures detected by said first temperature sensor and said second temperature sensor, and lead wires extend from said circuit substrate and are connected electrically to said mount terminals, wherein an insulation groove that passes through said circuit substrate in a thickness direction is formed between: a first lead wire closest to said second temperature sensor, wherein said first lead wire is electrically connected to said metal film, and said second temperature sensor; and said heating resistor.