The Japanese house bat or Japanese pipistrelle (Pipistrellus abramus) is a species of vesper bat. An adult has a body length of 3.6–4.8 cm (1.4–1.9 in), a tail of 2.9–4.0 cm (1.1–1.6 in), and a wing length of 3.2–3.6 cm (1.3–1.4 in). It prefers to roost under the ceiling or inside the roof of old buildings. It is found across East Asia, from China and Taiwan into the Ussuri region, the Korean Peninsula, and Japan.