The invention provides a sensor circuit and a sensor apparatus. The sensor circuit includes an illuminance sensor to detect illuminance of ambient light; and a proximity sensor to drive a light emitter, and to detect proximity of an object, based on an intensity of light emitted by the emitter and reflected on the object. The sensor circuit further includes at least one terminal among: a drive terminal for driving signal output of the light emitter; a detection result output terminal used for outputting a detection result of one of the sensors; a data input/output terminal used for inputting and outputting data compliant with a communication protocol; and a clock terminal used for inputting a clock signal compliant with the communication protocol, and a writable nonvolatile memory in whichtrimming data for correcting an individual variation of a characteristic of the sensor circuit is to be written. The trimming data input from at least one of the terminal is written in the nonvolatile memory.