The present invention provides a porous material which has continuous pores and comprises a polymethyl methacrylate as a main component, wherein the continuous pores have a diameter of 0.001 μm to 500 μm and at least one surface of the porous material has a porosity of 10% to 80%; a separation membrane composed of the same; an adsorbent composed of the same; and a method production of the same. A porous material whose surface porosity and pore diameter are each controlled in a specific range can be obtained. The porous material has a fine and uniform porous structure in which the pore diameter can be controlled in the order of nanometers to micrometers; therefore, it can be advantageously used as a separation membrane such as a blood component separation membrane of an artificial kidney or the like or as an adsorbent.