The present invention relates to a pharmaceutical composition for oral administration comprising a modified release portion containing tamsulosin or a pharmaceutically acceptable salt thereof, and an immediate release portion containing solifenacin or a pharmaceutically acceptable salt thereof and a hydrophilic substance.In the pharmaceutical composition, the dissolution rate of each drug (in particular, solifenacin contained in the immediate release portion) is similar to those of the current single drug formulations, and the maximum percentage of drag dissolution of each drug (in particular, solifenacin contained in the immediate release portion) is 90% or more. Therefore, the pharmaceutical composition is a single formulation (i.e., a combined formulation) with a bioavailability equivalent to those of the current single drug formulations.