Abstract: The invention discloses a method of repairing cracks, which is characterized in that, in injecting a repairing agent such as resin or the like into cracks occurring in an object to be repaired such as concrete, a masonry joint or the like, injection pressure of the repairing agent gradually increases after start-up of injection of the repairing agent and, further, the injection pressure is maintained substantially constant for a predetermined period of time after the injection pressure has reached a predetermined pressure, whereby the repairing agent is sufficiently spread into the cracks. Furthermore, the invention discloses a method of repairing cracks, in which the crack cavities are evacuated simultaneously with injection of the repairing agent, whereby the repairing agent is filled up in the cracks further efficiently.