Abstract: A portable parking meter including a main device and at least a sub-device; The body of the main device has two inserting slots for some sub-devices and is provided on the front face thereof with a control panel, the inserting slots are provided with some card interfaces capable of communicational connection with the main device when the sub-devices insert therein; The main device has a CPU which uses a reset loop connected peripherally with a keyboard interface, an oscillating loop and a LCD loop, and which has its internal timing program to establish the communication between it and the sub-devices, and it can count sequentially by the rate of value preset in the sub-devices for timing or reckonning times and deducting amount of charges in the sub-devices as a parking fee.