The present invention relates to hydrogel particles containing bubbles and having a specific gravity of 0.7 to 1.00 and an average particle diameter of 50 to 500μm, as well as a process for producing the same. The hydrogel particles may also contain hollow inorganic particles.本發明係關於含有氣泡,且比重為0.7~1.00、平均粒徑為50 μm~500 μm之水凝膠粒子及其製造方法。本發明之水凝膠粒子亦可含有中空無機粒子。