To provide a method for manufacturing a positive resist composition having small changes in sensitivity with time and an excellent spreading property of a developer liquid.

The method for manufacturing a positive resist composition containing a resin having a monocyclic or polycyclic alicyclic hydrocarbon structure and increasing the solubility with an alkali developer liquid by the effect of an acid includes a filtration process to filter the resin having a monocyclic or polycyclic hydrocarbon structure and increasing the solubility with an alkali developer liquid by the effect of an acid through an ion exchange filter. Preferably, the method includes a filtration process to filter the resin having a monocyclic or polycyclic alicyclic hydrocarbon structure and increasing the solubility with an alkali developer liquid by the effect of an acid through a filter which removes insoluble colloid.