The present disclosure relates to an insertion type drug injection device capable of being inserted into a body for injecting a drug into a skin, including: a main body having an open insert part and formed in a tubular shape having a hollow space therein, a needle assembly formed in the insert part, provided with a plurality of needles, and including a pneumatic port and a drug injection port, and a drug injection pipe inserted into the main body and connected to a drug injection port of the needle assembly, and an air flowing pipe connected to the pneumatic port.