To decrease measurement values at the initial stage of sampling having a high possibility of causing an error and to measure water content accurately, by processing data in data processing range time from the starting time of data processing as calculation values.

A tea leaf thrown into a crumpling chamber for measurement wait time 0-T1 is thrown from an intake port into a measurement chamber when sampling time T1 arrives. At this time, a water starts measurement. However, since measurement data being obtained until an amount of tea leaves required for measuring enter a measurement chamber may possibility contain an error, no measurement data are taken in until data processing start time T2. Then, when the processing start time T2 is reached, measurement data are acquired from the time T2 to sampling end time T3 (data processing range time). When the sampling end time T3 is reached, tea leaves in the measurement chamber are unloaded and returned into the crumpling chamber. All data are processed for detecting the amount of water during the above one cycle.