To oscillate a wideband triangular signal in simple structure.

An oscillator includes: a voltage-current exponential conversion section 100 including a base-grounded PNP transistor Q1 and a base-grounded NPN transistor Q2; a charge/discharge section 200 in which a non-inverting input terminal of an operational amplifier 10 is grounded and an output of the operational amplifier 10 is fed back into an inverting input terminal via a capacitor C1; a comparison section 300 in which an inverting input terminal of an operational amplifier 20 is grounded, an output thereof is fed back via a resistor R3, and one end of a resistor R2 is connected to the resistor R3; a variable resistance section 400 connected to the comparison section 300; and a temperature compensation section 500 connected to the variable resistance section 400 to temperature-compensate both transistor characteristics. An output of the comparison section 300 is fed back to the voltage-current exponential conversion section 100 via the variable resistance section 400.