Owing to prompt identifications of GRBs by Swift, the importance of prompt observations by ground‐based telescopes has recently increased. Multiwavelength observations are also important ever before because chromatic temporal variations have been reported in several early afterglows. Ground‐based observations with 1‐m class optical‐infrared telescopes are, however, inadequate in terms of the prompt observation. High energy gamma‐ray observations are also inadequate in terms of the multiwavelength studies. Our group has “KANATA”, the 1.5‐m optical‐infrared telescope whose characteristic is a high driving speed. We also join projects of the Wide‐band All‐sky Monitor (WAM) and the Gamma‐ray Large Area Space Telescope (GLAST). With these instruments, we are developing a prompt observation system for optical‐infrared afterglows with KANATA and a system for the analysis of multiwavelength data. The prompt observation system will be able to observe GRBs typically within a minute. The multiwavelength system can g...