Abstract: Disclosed is a film thickness detection device, including a common unit (1) and a detection unit (2); the common unit (1) comprises at least one common electrode (11); the detection unit (2) comprises at least one sensor chip (21) and a signal processing unit (23); the sensor chips (21) are opposite to the common unit (1) in a first direction and are arranged at intervals; the spaces between the common unit (1) and the sensor chips (21) form a transport channel for a to-be-tested film; each of the sensor chips (21) comprises at least one row of multiple detection electrodes (211) arranged along a second direction; the second direction is perpendicular to a moving direction of the to-be-tested film; the first direction is perpendicular to a first plane; the first plane is parallel to the second direction; the sensor chips (21) are configured to induce electrical signals on the common electrodes (11) and output the electrical signals; and the signal processing unit (23) is electrically connected with the sensor