A semiconductor device includes: a first read/write amplifier; a second read/write amplifier; a first group of bit lines belonging to the first read/write amplifier; a second group of bit lines belonging to the second read/write amplifier and mixed with the first group of bit lines. One of the first group of bit lines and one of the second group of bit lines are selected in parallel. A reference potential is supplied to at least one of the first non-selected bit lines adjacent to the first selected bit line selected from the first group of bit lines, and to at least one of the second non-selected bit lines adjacent to the second selected bit line selected from the first group of bit lines. At least one of remaining ones of the first and second non-selected bit lines is set into a floating state.