The peening apparatus (10) includes a processing tank (11), a table (21), a moving unit (49) including a nozzle moving device (50), a quill (52), a first head (53) having a mounting hole (53a) and disposed at a distal end of the quill (52), a motor (54) and a first spindle 58 exposed from the mounting hole (53a), a nozzle head portion (61) separable from the moving unit (49) and including a second head (65) having a connection port (65a) connected to the mounting hole (53a), a connecting shaft (66) connected to the first spindle (58), a second spindle (76), a nozzle (90) disposed below the second spindle (76), a nozzle flow path (87) penetrating inside the second spindle (76) and connected to the nozzle (90) to be opened to an upper end of the second spindle (76), and a swivel joint (81) disposed at an upper end portion of the second spindle (76) and connected to the nozzle flow path (87).