A transmission power increasing section continuously transmits, from a testing instrument to a mobile communication terminal at predetermined intervals, a transmission power increasing request for increasing transmission power of the mobile communication terminal by a predetermined quantity. A block size extracting section extracts, from a predetermined second physical channel, block size information indicating a block size of transmittable data defined in association with the maximum transmission power set at a first physical channel upon receipt of a plurality of physical channels from the mobile communication terminal for each transmission of the transmission power increasing request. A storage section stores, at least one time, block size information extracted at the block size extracting section. In the case where a value of newly extracted block size information in the block size extracting section is decreased below a value of immediately preceding block size information stored in the storage section as a result of comparison therebetween, the maximum output power state determining section stops transmission of the transmission power increasing request in the transmission power increasing section and transmits, to the mobile communication terminal, a transmission power decreasing request for decreasing transmission power of the mobile communication terminal by a predetermined quantity.