To provide a manufacturing method that causes few variation of size and hardness of necessary locations even if an error of a material supply amount is caused in simultaneous molding of many pieces of the concrete spacer block.

A pressure plate 6 that pressurizes an upper surface of a spacer block is divided into a reinforcement steel receiving part 8 of a center part and shoulders part 9 on both sides, and are made to be pressurized by providing the pressure difference between the center part and the shoulder part. Pressurizing of a spacer block shoulder part 2 is enabled corresponding to the variation of the amount at the material supply while the pressure plate shoulder part 9 slides by the pressure lower than the reinforcement receiving part 8.