An output correction apparatus that corrects offset drift of a cylinder internal pressure sensor, and a cylinder internal pressure detection apparatus that accurately detects cylinder internal pressure of an internal combustion engine through use of the output correction apparatus. The cylinder internal pressure detection apparatus includes a detection circuit section which detects a change in the resistance of a piezoresistor element as an electrical signal; an amplification circuit section which amplifies and outputs the electrical signal (output value); and a correction circuit section which corrects the output value. The correction circuit section includes a reset control section which resets the output value of the amplification circuit section to a reference value, and a reset timing detection section which determines a timing of the resetting.