A method for making a bit includes a step of preparing a bar of pre-set length, the bar having two lateral portions on two opposite sides thereof, and two engaging faces formed on each of the top and the bottom of the bar, the engaging faces being in contact with at least two face insides of a hexagonal hole of an accommodation tool, a distance X1 defined between the two engaging faces, a distance Y1 defined between the two lateral portions 11, X1≧1.2 Y1; a step of forming each of two ends of the bar into a function end, a connection portion being formed between the two function ends, and a step of obtaining the bit. The bit is compact and light weight.