PROBLEM TO BE SOLVED: To produce gallium oxide aggregates which have inter-particle cavity in an adequate range, are easy to be pulverized while having adequate strength, and can be compressed in volume during transportation.SOLUTION: The gallium oxide aggregates can be obtained by a production method comprising: a step of adding a gallium solution to an ammonium hydroxide solution to form a precursor by neutralization; a step of aging the generated precursor at a temperature less than 50°C (first aging step); a step of aging it at a temperature of 80°C or less (second aging step); and a step of calcining the obtained precursor after solid-liquid separation in atmospheric air (calcination step) to convert the precursor to gallium oxide.SELECTED DRAWING: Figure 2