A semiconductor memory device includes: a plurality of memory blocks; a plurality of bit-line sense amplifiers shared by neighboring memory blocks among the plurality of the memory blocks, and suitable for sensing and amplifying data read from memory cells coupled to activated word lines through bit lines, and outputting the amplified data through a plurality of segment data lines; a word line driver suitable for activating word lines of memory blocks that do not share the bit-line sense amplifiers during a test mode; and a weak cell detection circuit suitable for compressing the amplified data transferred through the plurality of the segment data lines for generating compressed data and detecting a weak cell based on the compressed data during the test mode.