We report the plasma production experiment in the central cell of the Hanbit device. In the experiment, an RF wave is excited by a slot antenna with a driving frequency of 3.75 MHz, and the RF power is applied up to 200 kW with a flat-top pulse length of 100 ms. The reproducible plasmas are produced without preionization with an averaged density of 2×1012 cm−3. The power absorption characteristics of the slot antenna are investigated by measuring the plasma resistance. The measured value of plasma resistance is in the range of 0.2 to 1.2 Ω. The discharges show transitions of the plasma density as the RF power increases.