A handheld punching device includes an operating grip pivotably connected to a holding grip to have a loading end turned in an up-down direction, a transmitting lever pivotably connected to the loading end to transmit a torque to turn a driving end, a punching seat pivotably connected to the holding grip and defining a cutting space for receiving a workpiece to be punched, and a plurality of punch units disposed between the driving end and the punching seat and each having a punch head movably and fittingly disposed in the punching seat along a straight path in the up-down direction, and a press head in abutting engagement with the driving end to be moved by the torque and to drive movement of the punch head through the cutting space for creating a hole in the workpiece.