A combustion chamber pressure gauge for an internal combustion engine, comprising a housing tube, a plunger, which is movable in an axial direction in the housing tube under the effect of combustion chamber pressure against a restoring force, and comprising a seal, which is disposed between the plunger and the housing tube, and comprising a sensor for detecting an axial displacement of the plunger. The sensor is decoupled from thermally induced expansions or contractions of the housing tube, in that the sensor is attached to a carrier, which is suspended in the housing tube, and the plunger is movable relative to the carrier under the effect of combustion chamber pressure.