A vehicle occupant protection apparatus 1 including: a first acceleration sensor (2) for detecting acceleration of a front portion of a vehicle (10); a second acceleration sensor 3 for detecting acceleration of a central portion; a integral initiation control device (15) for issuing an integral initiation command; the first acceleration integral device (16) for obtaining a first integral acceleration value of the acceleration of the front portion based on the integral initiation command; the second acceleration integral device (17) for obtaining a second integral acceleration value of the acceleration of the central portion based on the integral initiation command; a subtraction device (18) for calculating a difference between the first and second integral acceleration values; and the initiation determining device (20) for determining a type of the collision using the deference and starting an operation of the vehicle protection device (6) based on the determined type of the collision.