Oscillator

An oscillator outputs a control signal to suppress an influence caused by temperature characteristic of f1 based on a differential signal corresponding to difference between an oscillation output f1 of a first oscillator circuit and an oscillation output f2 of a second oscillator circuit treated as a temperature detection value. A switching unit switches between a first state and a second state. The first state is a state where a first connecting end and a second connecting end are connected to a storage unit for access from an external computer to the storage unit. The second state is a state where the first connecting end and the second connecting end are connected to a first signal path and a second signal path such that the respective f1 and f2 are retrieved from the first connecting end and the second connecting end to an external frequency measuring unit.