To provide a wood crusher and wood crushing method which can suppress the occurrence of biting of a foreign substance mixed into an object to be crushed.

In the wood crusher which has a side face frame 19, a crushing rotor 32 supported by the side face frame 19 so as to be able to freely rotate, a housing 41 rotatably provided at the side face frame 19, and an anvil 33 supported by the housing 41 to face a crushing room 31 around the crushing rotor 32, the anvil 33 rotates and holds the housing 41 in an evacuated position where the housing 41 evacuates from the crushing room 31, while a chute 73 is slid to a position across between the housing 41 and the crushing room 31 to perform primary crushing by crushing the object to be crushed supplied to the crushing room 31, and then while the chute 73 is slid to a position where the chute 73 evacuates from an area where the housing 41 rotatably passes through, the anvil 33 rotates and holds the housing 41 in a crushing position to face the crushing room 31 to perform secondary crushing by supplying the object subjected to primary crushing to the crushing room 31.