A device (10) for analyzing a circuit (14) includes at least one element (22) for observing light emitted by at least one localized observation zone of the circuit resulting from the electric current flowing in the zone; elements (26) for exciting the circuit. The circuit exciting elements include a laser source (26) and elements (30) for applying a laser beam generated by the source on the observation zone (22). The device includes members (M1, M2) for protecting the observation zone (22) against the incident and reflected laser beams.