A power and signal transmission device for a spindle of a machine tool is provided. The power and signal transmission device includes a spindle fixing portion, a shaft rotating portion, a power transmission component and a signal transmission component. The spindle fixing portion is provided with a power input end, a primary side power induction coil, a secondary side signal induction coil and at least one signal output end. The shaft rotating portion is provided with a joining end surface for bonding to a holder, a secondary side power induction coil and a primary side signal induction coil, and is rotatable with respect to the spindle fixing portion. The power transmission component transmits an electrical energy from the power input end. The signal transmission component transmits a holder signal to the signal output end. Each of the power and signal transmission components includes at least one elastic pogo pin.