The present invention provides a method of producing a nanoparticle dispersion liquid, including: altering a surface of a nanoparticle in the presence of an ion by contacting a complex that includes the nanoparticle and a solid material present around the nanoparticle with a surface altering agent-containing liquid, that includes a surface altering agent for altering the surface of the nanoparticle and a solvent for dissolving the solid material and that has a viscosity of 1.10 mPa·s or more at 25° C.; and a dispersing step of dispersing the surface-altered nanoparticle in the solvent.