Interplanetary dust particles are highly enriched with ³He implanted by the solar wind, enabling the reconstruction of extraterrestrial dust fluxes to Earth from sedimentary ³He records. However, the fluxes of extraterrestrial dust during periods predating the Cretaceous remain poorly constrained. In this study, we present the first comprehensive reconstruction of extraterrestrial ³He fluxes for much of the Triassic period (approximately 246–212 Ma) based on pelagic-bedded cherts preserved in Jurassic accretionary complexes in Japan. We reconstructed extraterrestrial ³He fluxes after correcting for dilution by radiolarian-derived biogenic silica. The records reveal long-term flux enhancements during the Ladinian and late Carnian (Tuvalian) intervals, reaching amplitudes approximately 2–3 times the background level and persisting for ∼3–4 Myr. These features are inconsistent with short-lived influx events, such as comet showers or asteroid breakups, and are instead comparable to long-term background variations in the Cretaceous and Cenozoic records. A sharp ³He flux peak at ∼215–216 Ma is accompanied by elevated ³He/⁴He ratios, indicating a sudden influx of fine-grained extraterrestrial material. The timing of this excursion closely coincides with the Manicouagan impact event (215.4 Ma), suggesting a link between asteroid disruption and enhanced dust production during the Triassic.