To provide a temperature change detection method of detecting a temperature change by a small number of additional circuits.

This semiconductor integrated circuit 010 includes: a voltage generation circuit 400 generating an output voltage Vreg depending on temperature; a PLL 500 including a VCO with the Vreg applied thereto; and a Vcnt detection circuit 200 outputting a detection signal Cup based on a level change of a VCO oscillation control voltage Vcnt controlling the oscillation of the VCO. The Vreg from the voltage generation circuit 400 is applied to the VCO 560 of the PLL 500. The oscillation frequency of the VCO 560 is changed by the value of the Vreg. That is to say, the oscillation frequency of the VCO 560 is changed depending on temperature. By a feedback operation of a loop of the PLL 500, the voltage level of the Vcnt being the VCO oscillation control voltage to be input to the VCO 560 is changed. The Vcnt detection circuit 200 detects the temperature change by detecting the level change of the Vcnt.

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