A spacing-adjustable cutting machine comprises a workbench. Supports are correspondingly and fixedly connected to the workbench left and right. A transmission shaft and a sliding rod are connected between the left support and the right support in parallel. The transmission shaft and the supports are relatively rotationally connected. The transmission shaft is in transmission connection with a driven wheel. A motor is fixedly arranged on the workbench or the supports. An output shaft of the motor is in transmission connection with a driving wheel. The driving wheel is in transmission connection with the driven wheel. The portion, between the left support and the right support, of the transmission shaft is in transmission connection with multiple parallel tooth discs. The sliding rod is fixedly connected with the supports and connected with multiple sliding blocks in a left-right sliding manner. Each sliding block is in threaded connection with a locating bolt. The slicing blocks are located to the sliding rod through the locating bolts. Hanging pieces are fixedly connected to the position below the sliding blocks respectively. The lower ends of the hanging pieces are relatively rotationally connected with tooth shafts. The tooth shafts and the tooth discs are arranged in a spaced manner one by one. One ends of the tooth shafts are in transmission connection with cutting discs. The other ends of the tooth shafts are meshed with the corresponding tooth discs through transmission teeth after the sliding blocks move to the corresponding tooth discs.