Provided is an inducing agent for megakaryocytes and/or platelets from pluripotent stem cells the inducing agent being useful in treating diseases involving thrombopenia. A method for producing megakaryocytes and/or platelets the method comprising: separating hematopoietic progenitor cells and cells that form a septum of a net like structure produced by pluripotent stem cells, in the presence of a compound represented by formula (I) (R^R 7, W, X, Y, Z, Ar 1, and n in the formula are defined in the specification), a tautomer of the compound a prodrug, a pharmaceutically acceptable salt of these, or a solvate of these compounds culturing the resulting hematopoietic progenitor cells in vitro and differentiating the same into megakaryocytes and/or platelets.
