It is intended to provide a resin foam which can be preferably used for medical use, and a flexible silicone type resin foam having a water-absorbing property. The resin foam which has a low toxicity and excellent physical properties for medical use such as moisture permeability, skin compatibility and low irritation can be obtained by using a resin which has a siloxane unit and an oxyalkylene unit in its molecular structure and does not contain a unit derived from an isocyanate group. Further, the flexible silicone type resin foam having a water-absorbing property can be obtained by allowing it to have a specific resin composition and a foam structure.