A valve timing adjustment device includes a driving-side rotatable body and a driven-side rotatable body. The driving-side rotatable body is configured to be rotated about a rotational axis synchronously with a drive shaft and includes a sprocket portion and a housing portion. The sprocket portion is configured to receive a drive force transmitted from the drive shaft. The housing portion is shaped in a tubular form and is formed separately from the sprocket portion. The driven-side rotatable body is configured to be rotated about the rotational axis synchronously with a driven shaft.