The initial deposition process of electroless nickel plating was investigated by combining a quartz crystal microbalance (QCM) method with microscopy. The authors found an anomalous deposition rate in the initial deposition and four stages were noted: an induction period before the initiation of deposition, an acceleration period with an increase in the deposition rate, a deceleration period with a decrease in the deposition rate and a stationary period at a constant deposition rate. The practical surface area of the deposits increased until the deposits became continuous and reached a constant value. On the other hand, the deposition rate per unit practical surface area decreased monotonously as the deposition proceeded. As a result, an anomalous initial deposition rate was observed. The four periods also appeared in the deposition when the catalyzation process was repeated 4 times. In this case, the number of grains at the initial stage was greater, and nucleation still continued until the deposits became continuous. The initial deposits, therefore, became continuous at lower thickness.