4-Azaindole derivative as shown below or a pharmaceutically acceptable salt thereof which are modulators of muscarinic acetylcholine receptor (mAChR) M1 and may be effective for the prevention or disease modifying or symptomatic treatment of cognitive deficits associated with neurological disorders such as Alzheimer-type dementia (AD) or dementia with Lewy bodies (DLB), and a pharmaceutical composition thereof as an active ingredient.