A detection device is used in a gaming machine that detects numbers of dots on a plurality of dice having wireless tags. The detection device reads the wireless tags which are embedded on each face of the dice by a reader having an antenna. The antenna of the reader includes a first antenna portion disposed substantially in a central portion of a field that supports the dice, and formed in a substantially circular shape, and a plurality of second antenna portions disposed so as to superimpose a detection area of the first antenna portion, and having a detection area larger than the first antenna portion. The first antenna portion and the plurality of the second antenna portions are disposed so as to have a portion of detection areas mutually superimposed on a playing board.