A method of testing waterproof performance of a radiological imaging apparatus including: a sensor panel including a plurality of radiation detecting elements two-dimensionally arranged a housing containing the sensor panel and an air pressure measuring unit configured to measure an air pressure in the housing having a vent hole allowing the air to flow into and out of the housing, includes: a load application step of continuing to apply a load to the housing an air pressure measurement step of measuring the air pressure in the housing with the air pressure measuring unit, the air pressure changing while the load is being applied to the housing and a waterproof performance determination step of determining whether the waterproof performance of the radiological imaging apparatus is normal based on a pattern of change in the measured air pressure in the housing.
