Abstract: A data processor (13) has a receiver for receiving measurement data on tires (21, 22) attached to an automobile (2) from a tire gauge (11, 12), and a data displaying portion for processing and displaying the received measurement data on a display (326) in a predetermined form. The received measurement data includes pressure value and tread depth of the tires (21, 22). The tread depth is measured on three points of inside, middle and outside in width direction of a tread surface of the tire. The received data is displayed in graphic representing positions of the tires (21, 22) of the automobile (2) and in a graph coloured corresponding to the measurement value.

Abstract: A main unit (21) attached onto rear side (opposite to a side equipped with a digital display) of a slider (14) and accommodating a transmission circuit inside to transmit measurement data by wireless, and an attachment module (40) to retain the main unit attachably and detachably to the slider are provided. Front profile of the main unit (21) is formed at least not to protrude beyond front profile of the slider. The attachment module (40) is constituted to be plugged into and unplugged from an output connector (18) on the slider (14), and has a connector (44) to connect the output connector and the transmission circuit in the main unit.