The present invention is intended to provide a compound or a pharmacologically acceptable salt thereof which is useful in the treatment of a tumor through its ROS1 kinase enzyme activity inhibitory effect and NTRK kinase enzyme inhibitory effect. The present invention provides a compound having an imidazo[1,2-b]pyridazine structure represented by the general formula (I) or a pharmacologically acceptable salt thereof, and a pharmaceutical composition comprising the compound. In the formula, R 1 , G, T, Y 1 , Y 2 , Y 3 , and Y 4 are as defined herein.