The present invention provides a method for efficiently manufacturing a non-enveloped virus with high purity without laborious operation by cultivating cells having the ability to produce a non-enveloped virus and bringing the cells and an acidic solution into contact with each other. A non-enveloped virus vector manufactured by the method of the present invention and a composition having the non-enveloped viral vector as an active ingredient are very useful as gene transfer methods in the fields of basic research and clinical application gene therapy.