A method for manufacturing an intraoral sensor having improved airtightness within its package is provided. A method for manufacturing this intraoral sensor comprises a first step S1 of arranging the signal cable 2 in a first mold, then filling the first mold with a first resin, and heating the first mold, so as to mold the cable connection unit 14 having the jacket 2c of the signal cable 2 welded thereto a second step S2 of preparing the joint 13 a third step S3 of arranging the cable connection unit 14 at a predetermined position in the joint 13 by using a second mold and a fourth step S4 of resin-sealing the joint 13 and cable connection unit 14 onto each other.