An LED tube lamp includes a lamp tube having a first pin and a second pin for receiving an external driving signal; a first rectifying circuit for rectifying the external driving signal to produce a rectified signal; a filtering circuit for filtering the rectified signal to produce a filtered signal; an LED lighting module configured to receive the filtered signal for emitting light; and a ballast detection circuit coupled to the first pin or the second pin, and coupled to the first rectifying circuit. The ballast detection circuit includes a switching circuit, and is for detecting whether the external driving signal comes from a ballast. And the ballast detection circuit is configured to control, based on a result of the detection, current conduction or cutoff of the switching circuit, to determine whether to conduct current by the switching circuit, which current bypasses a circuit path other than the switching circuit.