The invention relates to a thermal type air flow measuring apparatus comprising a body (6) which provides with a main passage (5) and a module which is integrated combination of an auxiliary passage (3) having a bent portion (303) and an electronic circuit (8) electrically connected to a heating resistor (1) disposed in said auxiliary passage (3), wherein said module is attached on said body (6) which has an insertion hole (14) through which said auxiliary passage (3) of said module is inserted into said main passage, said electric circuit (8) is disposed outside of said main passage (5), and wherein said body (6) has a mounting surface (15) for mounting said module thereon, said mounting surface (15) projects from an outer surface of said body, and an inlet (301) of said auxiliary passage (3) is placed in the main passage such that a position the inlet (301) is in an area shifted from a center of a cross section of the main passage and around the center of the main passage.