Convenient blade changeable knife

A blade changeable knife comprising:

• a first holding member having a first holding portion and a first connecting portion;
• a second holding member having a second holding portion, a second connecting portion, a flexible portion extending from the second connecting portion to the second holding portion such that the second holding portion is adapted to be flexed with respect to the second connecting portion, wherein the flexible portion is thinner than the second holding portion, wherein the second connecting portion is disposed on and connected with the first connecting portion, wherein the second holding portion and the first holding portion are disposed oppositely and configured to hold a blade therebetween, and wherein the second holding portion of the second holding member is adapted to be flexed to a holding position in which the first and the second holding portions are disposed close to each other and include a space therebetween for receiving the blade and a releasing position in which the first and the second holding portions are disposed apart from each other;
• and
• a locking device having a lock movably engaged with the second holding member, wherein when the second holding portion of the second holding member is in the holding position, the lock abuts the second holding portion of the second holding member, and wherein when the second holding member is in the releasing position, the lock abuts the second holding member and located away from the second holding portion.