Contact type one-way measuring device

The utility model belongs to the technical field of measurement, and particularly relates to a contact type one-way measuring device. The device is composed of a supporting plate, an adapter plate, a guide rail, a sliding block, a sliding body, a pneumatic driving device and a contact type measuring head, and the supporting plate is installed on a Z-axis moving assembly of a machine tool through the adapter plate and can move up and down under the action of the Z-axis driving device; the guide rail and the pneumatic driving device are both installed on the supporting plate. The sliding body acts on the guide rail through the sliding block and can move up and down along the guide rail under the action of the pneumatic driving device; the contact type measuring head is arranged at the lower end of the sliding body and can move up and down along with the sliding body; the contact type measuring head is connected with a machine tool control device through a signal line and transmits a measuring signal to a machin